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SNES S REPRE CEN O WN TS SOR ORTON a HTL TRO eee eS 


TOME AOE NE Ng Ee SON Ee OTE NERS NRRL PG CE ROY SNCS A RS CER ee 
: Seattet SE SESS ee 


eS Sa Ks. 
aan 


JOURNAL 


OF THE 


ROYAL 
MICROSCOPICAL SOCIETY: 


CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, 


AND A SUMMARY OF CURRENT RESEARCHES RELATING TO 
ZooLtLoGyY AND BOTAN DT 
(principally Invertebrata and Cryptogamia), 
MICROSCOPY, &c. AIBRARY 


Edited by 


FRANK CRISP, LLB. B.A, 
One of the Secretaries of the Society 
and a Vice-President and Treasurer of the Linnean Society of London; 


WITH THE ASSISTANCE OF THE PuBLICATION COMMITTEE AND 


A. W. BENNETT, M.A., B.Sc., F. JEFFREY BELL, M.A., 
Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College 


8. O. RIDLEY, M.A., of the British Museum, JOHN MAYALL, JUN., 


anp FRANK E. BEDDARD, M.A., 
FELLOWS OF THE SOCIETY. 


Ser. IIL—VOL' IV. PART 2, 


PUBLISHED FOR THE SOCIETY BY 


WILLIAMS & NORGATE, 
LONDON AND EDINBURGH. 


1884. 


The Journal is issued on the second Wednesday of 
February, April, June, August, October, and December. 


* 18 GSP a ; SRS DM WITS ; 

EME inte te ne Saree te es Soe 

DS Ser. IT. To Non-Fello 
Vol.IV.Part4.} AUGUST, 1884. | Beies be. 


JOURNAL 


OF THE 


ROYAL 
MICROSCOPICAL SOCIETY: 


CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, 


AND A SUMMARY OF CURRENT RESEARCHES RELATING TO 
ZOOLOGY AND BOTAN YW 
(principally Invertebrata and Cryptogamia), 
MICROSCOPY, Sc. 


Edited by 


FRANK CRISP, LL.B., B.A., 
One of the Secretaries of the Society 
and a Vice-President and Treasurer of the Linnean Society of Londen ; 


WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND 


A. W. BENNETT, M.A., B.Sc., F. JEFFREY BELL, M.A,, 
Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College, 
8, O. RIDLEY, M.A., of the British Museum, JOHAN MAYALL, Jon., — 
anD FRANK E. BEDDARD, M.A., 
FELLOWS OF THE SOCIETY. } 


WILLIAMS & NORGATE, 
LONDON AND EDINBURGH. 


CONTENTS. 


2039300 — 
TRANSACTIONS OF THE Sootmty— ae 
--XI.—Reseancues on THE STRUCTURE OF THE Grrwitke OF Draroms. 
By Dr. J. H. L. Flégel (Plates VIII. and IX.) .. . 605 
XII.—On a New Microtome. By C. Hilton Golding ts (Figs. 
SB adS4) ee aie ee meee uae Rui 823 


XITI.—On somz ‘Mora Meanree IN THE BLooD oF Viesnuies Aviuaus 
with Rerrrenoce To THE OocURRENCE OF BACTERIA THEREIN. ~~ 
By G. ¥F, Dowdeswell, M. A. FR. R. M. S., &e. on ee eur fe ee 625. P ; 


~ XIV.—On ProrosrongiA PEDICELLATA, A NEW OOMPOUND Inrusorivm. 


By Frederick Oxley, F-B.M.S. (Figs. 85 and 86)... .. 630 
XV. —QOn a New Form or Powarizine Prism.. By C. D. Ahrens) =~ 
(Figs. 87 and 88)... .. wees, gareiee 533 : 


Summary or Cugrent RESEARCHES RELATING TO oeigey AND! 4 
Botany (pRincipaLLy InveRTEBRATA AND Cryprocamia), Mioro- 
BCOPY, &c., INCLUDING ORIGINAL CoMMUNICATIONS FROM Frntows 
AND -OTHBRSS 3 516 iset sony ves Vane et ae tee Sig ee — 


te ‘ZooLoey. 

Polar Globules and other Elements eliminated from the Ovum 
Embryonic Germinal Layers and the Tissues... uiaiae 
Origin of the Mesoblast of Cartilaginous Fishes ies 

Intra-cellular Digestion in the Germinal Membrane of Vertebraies 
Larval Theory of the Origin of Cellular Tyee A GLE 
Development of Protovertebra ..  ..  . we 
Eaperiments in Arrested Development ..  ..  . 

Morphology of the Directive Corpuscles .. -s. ee. sn kt new SBT es 
Morphology: of the Pineal Gland: (<0 ewe EE ye na wees 


Segmentation of the Vertebrate Body =... 51 se se we 
- Embryology of Alytes obstetricans .. Pe acter 
» Development of the Nervous System of Forella Bes PP aay, : 
_ EIneubation of Eggs in Confined Air — Influence of Venitation te aN 
.. Embryonic Development’ .. Pa, F aeale 
Effect of High Pressure on the Vitality of Miero-organions nes be 
Micro-organiams of the Deep Sea... sey ereliGe vuera ine 


Origin and Formation of Glairine or Baregine a 
Organisms in Hailstones 


Suckers of Sepiola .. Pee os woe) eld val sigue ent ee 
Histology of Digestive System of Helis eee vik apis sales Somes oer ay lean 
Aplysiz of the Gulf of Naples . iS Ake ee rahe 


Morphology of the Acephalous Mollusen Le a iho 
Anatomy of Rhopalea .. wins 's oat aime sein toe tei Mean ales 
Luciola italica ..  .. 
* Development of Alcanthus niveus anit its ‘parasitic Teles. 
Origin of Bees’ Cells . Es 
Closed Poison-glands of Caterpillars Tdi Bae" tuy ext donee ae me vag eta 
Gills of Insect Larve.. .. Sie esis ee alg alc ae ON 
Dangers from the Hxcrement of Flies i ae 
Nerve-terminations on Antenne of Chilognatha ie 
Ovum of Geophili.... & 
_ Poison Apparatus and Poison of Scorpions Oe 
Structure and Function of the Liver of Renders vy 
Anatomy of Acarina .. .. Hee 
Sexual Colour-Variation in Crustacea 
. Observations on Tanais cersteds .. 
New and Rare French Crustacea 
Nervous System of Euniceidz .. 
Cerebrum of Eunice harassii, and, is relations to the ie Hypodermis 
penis of Branchiobdella var tans 


ee 


ee ee ae ee oe ee ee 


Loe oe oo) 


as: 


(38>) 
Summary or Current Resrarcues, &c.—continued. 


Ovum and its Fertilization (in Ascaris) .. 

Spermatogenesis in Ascaris megalocephala 

Spermatogenesis in Ascaris sag tg i 

Nematoids of Sheep’s Lungs 

wireptersng Nematodes = o-oo So Sou livsees Pian wet oe 
Peeehan tt? GRA TPYICRINOaI8 06 56 ses Soe No Socs Be: Noe YS 
Cystic Stages of Teniadz . eOee-eps est UN 
Anatomy and Development of Trematoda. be 
Worm-fauna of Madeira .. .. 


New Species of Rotifer — .. de 

Development of the Germinal Layers ae Echinoderms Saas wis 
New Genus of Echinoids .. wide aah fae 
Revision of the Genus Onda ono dee ong es vetiae 
Organization of Adult Comatulide .. BPD as ACS 9h te bake hee 
Anatomy of Campanularide +. 6. te te ee ne te 


Structure of the Velellide .. 00 wee ee a 

“ Actinizx of the Bay of Naples .. acetic g 
Morphology and Anatomy fof Citiatea Infusoria gatas 
Trichomonas vaginalis ., abe 
Acanthometra hemicompressa 
Orbulina universa PASS RSD ER a 7 
Nuclear Division in Actinospheerium eichhornit. .. amiiee 


Borany. 


Homology se Ge Reproductive Organs in Phanerogams feiie bones 


Influence of Light ‘and Heat on the Germination of Seeds Sohn oe 
Origin of the Placentas in the Alsinex (Caryophyllez) .. 1... 
Gemmz of Aulacomnion palustre. .. er 
Relation between Increase and 8 eqmentation of Celle! 


oe 


oe 


Development of he et ains in the Latietferous ot of the ie Buphorbiacee 


_ Constitution of Chiorop. 


Cellulose accompanying Me Formation of Crystals cpio eee 

- Middle Lamella of the Cell-wall .. et 

Intercellular Spaces between the Epidermal Calls of Petals . a 

an Contents of Sieve-tubes .. igs Tey 

_ Organs of Secretion in the Hypericacer lai aa gl ieknex Ronee es 

agi Sa ea lh pacar dee: a Lig apt Viks wet TRGB Rett OA 

_ Apparatus in Leaves for Reflecting Taye Mat: Snare StS 

_ Swellings in the Roots of Papilionacee ., ba a Te wleg ake as 

Origin of Adventitious Roots in Dicotyledones .. bets Kota patents 

Crystals of Silex in the Vascular Bundles... 1 se se ss 

Effect of Heat on the Growth of Plants .. 2. 6s ue ne ws 

- Curvature of Roots te 
Torsion as a Cause of ‘the Diurnal Position of ‘Foliar Organs : 


Assimilative Power of Leaves .. 

Quantitative Relation between Absorption of Light ‘and. ‘Assimilation 
Canses which Modify the Direct Action of rig it on nents: v 
Respiration of Leaves in Darkness ..  .. Poa ae 


‘Absorption of Water by the Capitulum 6 oebonie hayes 
trons di Ma ay a A Te Ti ALT ie er 


. Origin of Roots in TR Oy NOt ph Pee oT Oe eae 
Oe EMonogtag h of Lote e 
fs ge Position of Lepidodendron Sigilaria, | and. Stigmaria 
’ any. ariations. in Sphagnum . “* ” ** * ad a 
- Sexual oduction in Fun Geis, We tah) Se Mads ge Ke 1). ig 
_ Life-History of Acidium bellidis DC. oo. (4abe) Bak 
- Rpharopta and Affinity of Senere seer Boluvvinite ap i'o0 (lop 
oc ew waa: on the Silver-fir . -- oe ’ ” oe ” 
, ~ “Micrococcus prodigiosus within We Shell of an i Bag Prva Was oF 
ig ood * : “* “* “sb 
af Wat i * } ye ee - ’* * ” 
Barbus of Chola ” oe ** “- -* “ee “* Re}! 


KY . Virus of Anthras. - * “* oe ae * ” oo ” o 


41) 


Summary or Current Reskarouss, &c. —continued. 


: _ PAGE.) > 
Attenuation of Virus in Cultivations by Compresied Onygen ve ee ae OOD 
‘Rabies... -<- we ee ee ee we 600 
Bacteria in Canals and Rivers ee ue SSE aS ti ee) 


Bacteria from Colowred Fishes’ Eggs sip owas ae ee oe d'or ein Sega) aol Ca 
Bacteria connected genetically with Alge «sve ee ed te we oe COL 
Action of Oxygen on Low Organisms =... xe we oe ne ne oe GOB 
Biology of the Myxomycetes 2. se ng te te ee ee ae ee ee B08 
Cephatodia of Lichens woo 30. emg en og ey) ee!) (Bat eg 2 we aaa ee = OU 
Thallus of Lecanora hypnum saOy ap Ede Weeks aihale Unectee iat aw iat ree eee OLD 
Systematic Position of Ulvacex BEA REE we eat ee ok cab pros aias etre eaetta ED 
Newly-found Antheridia of Floridew  .0 ve ue ae ne ee ee te 0G 
New Unicellular Algz-.  .. Se GR arel tne Pia Le wen Miele aa atROL 


Structure of Diahower:.. 8 S50. Cee en ews Coaypi men mee eae + oe eee OES 
Belgian. Diatoms .. a Es Gn,2 (an ancien ee brace eee eens 
Didiomacer from the Island of ‘Socotra’. er he Lr ee ie en eh 
Microscory. v chat 
Microscope with Amplifiers (Pig. 89) -. 1d. Wi se bavi Rlpeas Vaan Maa deat 
Bausch’s Binocular Microscope (Figs. 90 and 91)_ Be Meeurrna sweat Li 
Sohncke’s Microscope for Observing Newton’s Rings (Fig. 92) Sipigae sas ec OUG 
_ Harris and Son’s Portable Microscope (Figs. 93 and-94) >. vs a Se 611 
Seibert’s No. 8 Microscope (Fig. 95) ws OLS 2 
paca Large BS es Microscope and “Hand Magnifiers Figs. 96. AD is 
and 97)... S 613° 


Geneva Companys Dissecting Microscope (Fig. 98) Ee gen hee » 614 
Drailimand Oliver’s Bie o0k? ee Mis: eee SU ere raa ynh pio ents vee ving at 07 &: Sige 


Ward’s Eye-shade (Fig. 100) . : + Raa eye aimee ats eal oy Ii alps 
Findomersion Objectives —... Fes bio bd ORAS ah te yids tod eee a erat aes 616. 
Selection of a Series of Objectives sey pralul| agsericg ee OO reat 
Correction-Adjustment for ‘Homogeneous-Immersion ‘Objectives +5. scape OSU 
Lighton’s Immersion Illuminator (Fig. 101)...” sich cs thee 


~ Illumination by Daylight and Artificial Laight —Parabeloids and Liebertiina 621 
Bausch’s New Condenser (Figs. 102 and LOB) re oe hk aes ioe aerial aed 
Glass Frog-plate (Fig. 104). 623 AR 

Groves and  Cash’s hs a for iMioresngat “and Phot AS 

Observations (Fig. 105) ... .. 624. 


Visibility of Ruled Lines .. Saree aaa eh no -3, 625. : 
Mercer’s Photomicrographic. Camera ig. 106) Fe stacey ented Sue ERD 
Photographing Bacillus tuberculosis ist Bei ake ibn ce Ups eee A St 


- Beck’s,.** Complete” Lamp (Fig. 107)... GaP naphiny wae sieye 
James’ ‘ Aids to-Practical Physiology’ 2. +. ee os ue a 
Postal Microscopical Society .. Ree aap Meee Nt ta 
Methods of Investigating Animal Cella ef ies Roe ae see 
Born’s Method of Reconstructing Objects from Mictoecopie Sections Pan: 
Shrinking Back of Legs of Oribatidz in Te ak ist Aes. oe ot dea Weteed Oaeeera 
Preparing the Liver of the Crustacea .. Sere ga eae Rae eS 
Preparing Aleyonaria... .. Eats t 
Semper’s Method of making Dried Preparations . eC tole « O87 
Method of Detecting the Continuity of Protoplasm in Vegetable Siriiciiecs < 687, a 
Method of Preparing Dry Heo scopse Plants fos the eee eer tg Sn ORE 
Chapman’s Microtome —_.. as : 


Use of the Freezing Microtome . wee 
ae for Injection—Fearnley's Constant Prewure Apparaiae ies 
Myrtillus Yen ‘Staining “Aniintl and Vegetable Tissues . ia Gate tates tan 
__. Hartzel’s Method of Staining Bacillus tuberculosis... |... we 
' Safranin Staining for Pathological fens Ei eae 
~~ Collodion as a Fixative for Sections .. 
~ Piffard’s Slides .. ., ee Peierls 
Mounting. in Balsam in Cells... 
Styran, Liquidambar, Smith's and, van Hee ited 
Grouping Diatoms .. aes 
Quantitative Analysis of Minute Aerial Organisms 


or ‘on = 


Microscopical Evidence of the pate) of Articles ues Stone Sa 
PROCEEDINGS OF THE Sociury 


ove ee 


Go) 
ROYAL MICROSCOPICAL SOCIETY. 


COUNCIL. 


ELECTED l3sth FEBRUARY, 1884, 


PRESIDENT. 
Rey. W. H. Dauuinerr, F.RS. 


VICE-PRESIDENTS. 
Joun Antuony, Esq., M.D., F.R.C.P.L. 
Pror. P. Martin Duncan, M.B., F.R.S. 
James GuaisHeEr, Esq., F.R.S., F.R.AS. 
_. Cartes Stewart, Esq., M.B.CS., F.LS. 


| TREASURER. 
Lionex §. BEALE, Esq., M.B., F.B.C.P., E.BS. 


SECRETARIES. 
Frank Crisp, Esq., LL.B., B.A, V.P. & Treas. LS. 
‘Prov. F. Jerrrey Bern, M.A., F.ZS8. 


Twelve other MEMBERS of COUNCIL. 
AurgeD Wiiuiam Bennet, Esq., M.A., B.Sc., F.LS. 
_ Roser? Brarrnwarrs, Esq., M.D., M.R.CS., F.LS. 
G. F. DowpEsweux, Esq., M.A. - 
J. Wit11am Groves, Esq. 
 Jouy E, Inarun, Esq. 
Joun Marrnews, Esq., M.D. 
Joun Mayan, Esq., Jun. 
Auzert D, Micnann, Esq., F.LS. 
Jonn Mrizar, Esq., L.R.C.P.Edin., F.LS, 
Wiuuam Mirnar Orp, Esq., M.D., F.R.O.P. 
Unean Pritcnarp, Esq, M.D. 
Wuu1sm Tuomas Surrorx, Esq. 


LIBRARIAN and ASSISTANT me eastaate 
Mz. James West, 


C65) 


I. Numerical Aperture Table. 


The “ APERTURE” of an optical instrument indicates its greater or less capacity for receiving rays from the object and « 
transmitting them to the image, and the aperture of a Microscope objective is therefore determined by the ratio. 
between its focal length and the diameter of theemergent pencil at the plane of its emergence—that is, the utilized’ 
diameter of a single-lens objective or of the back lens of acompound objective. ee 


This ratio is expressed for all media and in all cases by  sin'w, 2 being the refractive index of the medium and a the 
semi-angle of aperture. The value of m sin'y for any particular case is the ‘numerical aperture ” of the objective. 


88,688 | 1-087. 
86,760 | 1*111. 
84,832 | 1-136" 
| 82,904 — 


* Diameters of the Angle of Aperture (= 2). . Theoretical’ P : 
Back Lenses of various : : Ilumi- |: Resolving » pate 
Dry and Immersion Numerical = Water- | Homogeneous-| nating Power, in _ | trating 
Objectives of the same Aperture. Ob ay Immersion| Immersion’ | Power. | Lines to an Inch, Power 
Power (4 in.) (m sin w= a.) yieetives: Objectives.| Objectives. | (@%.) | (A=0°5269 @) (-) 
from 0°50 t0.1°52.N, A. @=1) lm =1-33,)| (n= 1°82.) ‘sline BK.) | Na? 
1:5 os xe 180° 0!) 2°310)° 146,528 | 
1:5 ae a 161° 23’ |2°250| 144,600. |. 
1:4 ee oe | 158°. 39! | 2-190). 1425672 | *67 
1:4 BA 147°: 42?:| 2°132 140,744 | +68 
1:4 A 142° 40" |2:074| 188,816" 
1:4 we ob 138° 12’ | 2°016} °136,888 © 
1:4 * oe! 134°.-10" |1-960) 134,960. - 
1:3 ais so + 180° 267) 1°904)-. 183,082. | +725: 
1-3 os ‘ 126° 57’) 1°850|° 131,104 7} 
1°3 : Ma 123°: 40’ |1°796) » 129,176 © 
1°3 as |180°° 0’) 122° 6’ }1°770) «128,212. 4° =7. 
1-3 5 165° 56’| 120° 33} 1:742|> 127,248 | «= 
1°3 ws 155° 38’|. 1179-34’ |1°690) 125,320: 
» 12 148° 28’) 114° 44’ |1°638} 123,392 4 
1-2 |. [149° 89°] 111° 59’ 11-588} 121,464 | - 
1:2 oe 187°.36'| 109° 20’ | 1°538) 119,536 7)" 
- 172 ae 183° 4'| 106° 45' | 7-488] 117,608 pas ee 
~ 1:2 KG 128° 55’| 104°-15' | 1-440]: 115,680} 
i ie b oe 125°° 3’). 101° 50’ | 1°392 113,752}. +84 
1-1 <s 121° 26’) 99° 29' | 1*346)- 111,824 |. "862° 
1-1 oa 118° 00'| . 97° 11’ |1°300 109,896 | +, 
esded 114° 44/) 94° 56’.|1°254) 107,968 |: : 
1-1 ate 111° 36'| 92° 43’ |1-210} 106,040 | *! 
1:0 5 108° 36’| 90° 33’ |1°166} . 104,112 . | 
1:0 Se 105° 42’| 88° 26' | 1-124] 102,184 | is) 
“1-0 102°. 53'|- 86° 21' |1-082| »100,256 9) = 
1:0 we 100° '10’| 84°. 18'-|1-040| 98,328 | = 
zk 180°, 0’ |. 97° 31’) - 82° 17" |1:000}'~ 96,400 | 1- 
O- 157° 2! | 94° 56’) 80° 17’ 960} ~ 94,472  } 4-4 
QO: 147° '29' | 92° 24"). 78° 20’ 922) 92,544" [ods 
& 140°). 6! | -89°° 564). 76° 24! | °884 90,616 | 1*064~ 
0- 
0- 
0: 
0: 
» oO: 
O 


62° 40’ 
60° 0". 


TNANATDADHDOA AH IIITIINOD HON WOOOOGS 
SVR AROVKHADOWHARDOWHADOWVPAHDOOHADOVMADOWOHADOWHHADOWRADOW 


114° 17’ | 78° 20"). 67°. 6’ | +706} 80,976 | 1:190° 
110°. 10' | 76° 8’| 65° 18’ | °-672 9,048 | 1°290- 
0- 106° 16’| 73° 58’| 63°31 | -640 
0: 102° 31’ | 719 49'| 61° 45' | <608 
0: 98° 56’ | 69° 42"| 60° 0"! -578 
0: 95° 28’ |} 67°. 86... 58° 16’ | +548 
OF 92° 6! | 65° 32’) 56° 32’ | +518 
_ 0- 88° 51’ | 63° Bl’) 54° 50’ | +490 
0° 85° 41’ | 61° 30'| 53° 9’ | +462 
0- 82° 36’ | 59° 30") 51° 298’ | +436 
-0: 79° 35'| 57° 31") 49° 48’ | +410 
0: 76° 38' | 55° 34’) 48° 9’ | +384 
oO: - 78°. 44" | 58° 88’| 46° 30’ |. +360 
- 70° 54’ | 51S 49") 44° 5 | - B36 
0: 
QO: 
0: 


trae ese ee tit 
 fixawpnr.—The apertures of four objectives, two of which are'dry, one water-immersion; and one oil-immersion, - 
| HRAMP b Dich are’ = e oil-imm ie 
_ > would be compared on the angular aperture view as follows i106? (air), 157° (air), 142° (water), 130° eae 
Their actual apertiives are, however, ag Goan ; 480-> °° *98. 226 ) Fea or their 
smumerical apertures: j : Uke iC aoe aaa 


Gt) 


; II. Conversion of British and Metric Measures. 
Gi.) Lineat. 


* Seale showing | Micromillimetres, §c., into Inches, §c, Inches, §e., tuto 
the relation of | f ins. min. ins. | mm, ins. Ne raat: 
ma iene | 1 000039 | 1 039370 | 51 2°007892 | — ins, i 
&c., to Inches. 2 -000079|; 2 -078741| 52 2°047262 | _ 1 1-9]599) 
mm 3 -000118| 8 11isll| 53 2°086633 | ~"2°" 1 -p¢9989 
and 4 -000157| 4 *157482| 54 2°126003 | 77x" 1-693318 
ny fe, 5 -000197| 5 196852 | 55 2°165874 | 1" 9-539977 
n= ay 6 -000236) 6 236223} 56 2-204744 | 7°2°°. 9. g5o197 
=e 7 -000276| 7 *9275593 | 57 2°244115 soso. 3°174972 
[Ea | 8 000315! 8 -314963| 58 2°283485 | 2” 3-628539 
lee | 9 +000354| 9 354334 | 59 2°322855 | —"v" 4-933995 
= | 10 -000394) 10 (lem.) *393704| 60 (6cm.) 27362226] f°" 5.079954 
EF | +41 000433) 11 -433075 | 61 2401596 | ac05 6° 349943 
eee ee Be Oe 
= 000512 | 1 “511816 "480337 | soso 12° 5 
A i 14 +000551| 14 551186 | 64 2°519708 | rao 29°399772 
Ea | 16 000591 | 15 “590556 | 65 2°559078| Be 
E F| | 16 --000630| 16 629997 | 66  B598hi9} ato 0282 
2s | - 17 -000669 | 17 “669297 | 67 2-637819 | rao Pat OO 
lz = 18 -000709| 18 708668 | 68 2-677189] Too bay: 85 
=a 19 -000748| 19 -748038 | 69 2°716560 | som hedena 
[Fs 20 "000787 | 20 em) +787409| 70 Tem.) 2-755930]} Fyn | pein 
=m 21 -000827| 21 “826779 | ‘71 2:795301| #8" ggg 
E z| | 22 -000866| 22 “866150 | 72 2-834671; 33° Pibiessi 
E sian 23° -000906 | 23 905520 | 73 2°874042| =i - 084666 - 
Fat] |, 24 -000945| 24 “944890 | 74 2°913412] 21" -101599 
| | - 25 -000984! 25 -984261| 75 2-952782] J -196999 
=F | 26 -001024| 26 1:023631| '76 2:992153| 53" 169332 
a 27 -001063) 27 1°063002| 77 3°031523| 13° — -953998 
== 28 -001102/ 28 1:102372| 78 3°070894 | 2" 507995 
Ey 29 -001142| 29 1141743} 79 3110264] 2 1.015991 
f Es |) 80 001181 | 80 Sem,)1°181113 | 80 em.) 3°149635 as. 1°269989 
i =| baba a 31 001220 81 1:220483| 81 8:189005 | yy 1587486 
= il “001260 | 32 1:259854 | 82 B:298875: | ae. 1" 
5 = 5 |) - 83 -001299| 33 1-299224| 88 3267746 | ve 2116648 
AB 34. -001339| 34 1°338595 | 84 3°307116 |. vo . 2°539977. 
IBRL | | 85 001878 | 35 1-377965 | 85 3°346487 | a > 8174972 
aH _ || 86 -001417; 36° ~—:1-417336 | 86 3°385857 | 3 £°283295 
E ay 37 -001457! 37 1456706 | 87 3*425228} r%  4°'762407— 
= | 38 -001496 | 88 1°496076 | 88 3°464598 |. &  5°079954 — 
fe =! 39 +001535 | 39 1:535447 | 89 3°503068} 4 6349943. 
; es 40 ‘001575 | 40 (4cm.)1°574817| 90 (9 em.), 3:543339] as Led ogi 
| A 41 -001614| 41 1-614188| 91 3582709 | * cm 
al: 4 42 +001654| 42 1:653558| 92 3:622080] 2 1-111240 
| Be 43 -001693 | 43 © 1:692929 |, 93 - 3-661450] 2. 1269989 
als ia 44 +001732| 44 1-732299| 94 — — 8*700820]° 9 1 -499787_ 
wee | 45 -001772| 45 1:771669 | 95 3°740191 |g 1587486. 
af 1B . 46 ‘001811| 46 1°811040| 96 B°779561) 44 -1+746234 
rer = §| - 47 +001850| 47° 1°850410.| 97 -8°818932 RY 1°904983 
mal: - 48 -001890 | 48 1°889781| 98 3858302} ay -9-068732 ~ 
mule = 49 -001929! 49 ites 99 3897673] 2 2-222480 — 
| BBE 50 -001969 | 50 (5 cm.) 1+968522 | 100 (10 cm.=1 decim.) }# | 2°381229 | 
maiz: 60 -002362 1B) 2:589977: 
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tales 400 +015748 6 28'622259 8. '2-031982 
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pe ae | 700 1027559 9 85 °483389 11 2°793975 
(10mm,=1em || 800 -031496 10 (1 metre) 39°870432 1ft 3047973 
10 cm. =1 dm. : 900 * 035483, | , = 3° 280869 ft. ‘ yea al 


0 ass. se. 1000 (=1 mm.) | Oa = 1093623 yds. lyd.= +914392 


< J 
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TRANSACTIONS OF THE SOCIETY. 


XI.—Researches on the Structure of the Cell-walls of Diatoms.* 
By Dr. J. H. L. Fugen, 


(Read 12th December, 1883.) 
Puates VIII. anp IX, 


THE various objections made to my previous researches have induced 
me to undertake a re-investigation, and although this has for the 
most part been simply corroborative, it has appeared to me desirable 
to publish the results, together with some obtained in reference to 
other diatoms of which only preliminary communications (7) have 
hitherto been published. . 

Day by day the old erroneous views on the structure of diatoms 
are repeated in the text-books of Botany, and nobody seems to have 
approached the subject seriously ; the present paper may therefore, 
I hope, arouse sufficient interest to induce further investigation. 


I. Meruop or INVESTIGATION. 


I have already (6) described the methods which I have followed 
in the investigation of Pleurosigma ; but it is necessary to refer 
here to the method of section-cutting. In applying my greater 
experience to Plewrosigma and other diatoms I have obtained 
generally much better results than formerly, which have lent addi- 
tional confirmation to my paper of 1870. 

Time of making Sections.—Accidentally I made my original 
investigations during the summer. When in the winter I wanted 
to replace some preparations, I found it impossible to obtain success- 
ful results. ‘The cause was the artificially heated room. It is 
useless to attempt to bring the gum to the right degree of hardness 
by the addition of glycerin, sugar, &c., as, in consequence of the 

* The original paper is written in German, and has been translated by 
Mr. J. Mayall, jun, 
Ser, 2.—Von, IV. 2M 


506 Transactions of the Society. 


proximity of the face and the hands, the aqueous contents of such 
strongly hygroscopic substances are subject to an uncontrollable 
change, so that we must work with pure gum arabic and in the 
summer. 

Slight differences are caused by the weather or by the position 
of the sun. Sections of the coarser diatoms which are not required 
to be of extreme thinness are best made with a clouded sky or in 
rainy weather. Sections of Plewrosigma succeed best when the sun 
shines directly into the laboratory without striking upon the Micro- 
scope. I can hardly too strongly dwell upon the necessity of 
entering upon such experimental investigations under the best 
physical conditions, absence of vibration, noise, &c. : 

Placing the Frustule.—By my earlier method sections in 
different directions were obtained hap-hazard because the frustules 
were lying pell-mell in the gum. I have now improved the method 
as follows :—I take a number of frustules like a bundle of rods and 
cut sections in the exact transverse or longitudinal direction. With 
this important but difficult method every one must become familiar 
if he intends to check the results (hereafter described) which I 
obtained with Pinnularia. 

(1) If we wish to examine uninjured specimens, the diatoms are 
first stained, usually by picro-carmine; they are then put in absolute 
alcohol. A glass slip is coated with collodion, and allowed to set. 
To avoid peeling when dry, the collodion must not be too thick. A 
drop of thick gum is then put on. A cluster of diatoms is taken 
direct from the alcohol with forceps and placed. in the gum. In 
consequence of the current set up, the diatoms immediately distribute 
themselves equally through the gum. As soon as the edge of the 
gum begins to harden, one frustule after the other is drawn to the 
edge by a very fine needle, where, with proper manipulation, they 
can be piled up like a bundle of rods. All those which interfere with 
this piling up should be removed. Owing to the staining, the 
frustules can be readily seen on the transparent ground. As soon 
as the edge dries, a drop of fluid gum is added by a needle, and this 
process is repeated until the solid layer of gum has reached such a 
thickness that a displacement of the frustules need be no longer 
feared ; a small patch of collodion is then put on. The preparation 
is now cut out by four cross-cuts and carefully removed from the 
glass ; the bundle of diatoms in gum being contained between two 
films of collodion. It is advisable to make a drawing with a high 
power to show the position of the individual frustules and aid in 
the identification of the sections. The preparation is then put 
upon a nearly dry flat drop of gum on a piece of cardboard, and the 
base and the edges are made to adhere, if necessary, by a few drops 
of water, and by the addition of minute drops of gum it is so im- 
bedded that at last it is entirely surrounded. This must be carried 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 507 


out so cautiously that the collodion films do not separate; very 
careful watching of the imbedding process is therefore necessary, 
especially also to avoid cracks which commence at the edge and 
might easily extend to the object. From this bundle, sections may 
be made according to the method described by me in 1870. 

(2) Any one wishing to study the structure of the individual 
valves and mark their manner of combination can shorten this 
somewhat detailed process. A cluster of diatom valves is taken 
out of the alcohol and placed in a large drop of water on a slide ; 
and the water is allowed to evaporate after the valves have been 
evenly distributed. A drop of gum already dry—if possible with 
a flat surface on a piece of cardboard—should be in readiness ; 
another piece of glass is coated with oil of turpentine, which is 
allowed to run off so that a very thin film is left, which does not 
readily dry. In this the point of a fine needle is dipped vertically, 
taking up sufficient oil so that by touching a frustule lying on 
another slide it will adhere. Thus the frustule can be put on 
the hardened drop of gum which has been moistened by the breath ; 
this is repeated with a number of valves ad libitum, and finally 
they are covered with minute drops of gum till the required 
thickness is attained. This transference of dry frustules upon 
the dry gum is much easier than the process with fluid gum 
described under (1), because, with the latter, it frequently occurs 
that in bringing a new frustule into place the others are disturbed. 
With uninjured frustules process (2) is not available, because 
these, after the drying of the thin upper layer of gum moistened 
with the breath, will at once become charged with air and baffle 
any cutting. This absorption of air can only be avoided by trans- 
ferring the frustules from the alcohol directly into the fluid gum, 
which then diffuses equally through them. At the most the 
frustule at the moment of hardening is slightly compressed, which 
injures somewhat the appearance of the sections. 

Making Sections.—Numerous attempts to cut diatoms on the 
microtome failed, and I always returned to cutting by hand, under 
a dissecting Microscope. Gum is not favourable as the imbedding 
medium for the microtome. If a better medium were discovered 
(paraffin is useless), then a new era would open for these researches. 
Knives with broad backs should be employed; the angles of 
inclination to the cutting edge I have used are 21° 20’. 

Piling-up of the Sections.—Ptitzer (19, p. 42) formerly pro- 
posed to moisten by the breath the gum-chips containing the 
diatom sections after they had been put upon the slide, whereby 
they naturally adhered. Anything more unpractical cannot be 
imagined; the very thing one wishes to avoid—namely, the dis- 
turbance of the sections—is by his method certain to occur, and in 
the most favourable case we have a hardened drop of gum in 

2M 2 


508 Transactions of the Society. 


which are scattered all sorts of fragments of the diatom sections, 
which the observer may be able to define with reference to their 
previous position, but which are utterly useless for the study of real 
details of structure. The unavoidable proximity of finger and 
face during the cutting is injurious, because the immediate sur- 
rounding atmosphere of the operator always contains a quantity 
of moisture which causes the delicate chips of gum immediately 
to adhere. In piling-up the sections we should most carefully 
avoid every increase of moisture, and during the operation 
the breathing should be suppressed. If after discharging the 
sections from the knife we do not intend to put on the cover-glass 
at once, then the slide with the chips should only be lifted up when 
in sunlight and under protection from dust. As a rule, time 
should not here be lost. It is advisable before putting on the 
coyer-glass to touch two corners, which first come in contact with 
the slide, with small drops of balsam, so that during the lowering 
of the cover-glass it does not slip out of place and so grind up the 
very brittle chips of gum. The lowering of the cover-glass should 
be done slowly and steadily. If let fall, the puff of air will blow 
away the chips. If the chips, on account of too little moisture in 
the atmosphere, are curled up, the cover-glass will flatten them 
out, the gum on the edges may split, but the centre becomes 
flat_and is often very useful. In general, however, it is recom- 
mended, on the days when these difficulties occur, to postpone the 
operation. Once for all, I state that flat sections are always the 
most instructive. After putting on the cover-glass a proportion- 
ately small drop of thin fluid-balsam is added on the edge—only so 
much that the sections are imbedded in it. After a few days the 
vacant spaces are filled up by fresh drops of balsam ; a derangement 
of the previously filled-up sections is no longer to be feared. 

Series Preparations.—With Pinnularia the making of: series 
sections is almost a necessity, especially for the longitudinal sections, 
My procedure is as follows, though I am well aware it is capable 
of improvement. I cut off No. 1, leaving it on the edge of the 
razor ; then I take a second section a little further off, and so 
on, until five are on the edge. These I transfer to the slide 
with a needle, and as nearly as possible in a straight line. This 
is repeated with the other five sections which form the second 
line. Then I take a new slide, and thus get decades of sections 
from a bundle previously prepared. A disadvantage is that some- 
times the sections do not remain on the edge; by falling upon the 
table they are lost. Also that not seldom one cuts a gum-chip 
as a numbered section, which on further examination proves never 
to have touched the bundle of frustules. By disregarding these 
very troublesome mishaps, the series-section method according to 
my view gives the most beautiful results obtainable with such 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 509 


delicate objects. As an example, I may mention a bundle of 
P. balticum in my possession in 150 sections, of which 100 were 
successful; of these about 70 could be identified as being from one 
frustule. 

Preservation of Preparations.—This subject is unfortunately 
for me at the present moment one of the most troublesome. One 
would anticipate that by taking quite dry gum imbedded in balsam 
slowly hardened, the preparation would be almost indestructible. 
I regret to say this is not always the case. My preparations 
of 1869 remained stable six to seyen years. But afterwards 
a fatal change took place with many. The sharp straight edges 
of the gum-chips lost their sharpness, the edges rounded off, and 
lastly a kind of oil-drop took their place, in which the former 
beautiful sections almost disappeared. Whether my present house 
is too damp, or whether moisture works through the balsam along 
the glass up to the sections, I do not know; but I suspect some- 
thing of the kind. The serials I made last June and July have 
kept in partibus well up to the present, but a portion commenced 
in October to change, although as a protection I had covered the 
edges with asphalt and kept them in a room which was warmed 
every day. ‘The real cause of the destruction of these preparations 
is still a mystery, and I would recommend that sections should 
be studied immediately after being made. 


II. Resvuuts oF THE INVESTIGATIONS. 


My first paper was confined to the varieties of Plewrostgma, and 
I now give an account of all the other diatoms the structural details 
of which I have investigated. I may at once say that a general 
sketch of diatom sculpture cannot be given. We cannot take the 
structure discovered by me in Plewrosigma (consisting of chamber- 
like holes in the interior of the cell-membrane) and thus explain the 
structure of all diatoms, nor can we conclude from Moller’s proved 
structure of Triceratiwm (viz. chambers open externally) that this is 
the same, mutatis mutandis, with all others of this numerous order. 


1. Pinnularia. 


Probably the cellular envelope of a great number of diatoms 
follows the type of Pinnularia, which may therefore be put first, all 
the more so since the views regarding their structure (chiefly based 
on Pfitzer) adopted in most text-books, are totally erroneous. 
Moreover, the structure of their cell-walls is very remarkable. For 
my material (Pinnularia major) I have again to thank Herr J. 
D. Moller. It consisted principally of isolated valves which were 


510 Transactions of the Society. 


treated by different methods, viz. (1) by the section method, (2) 
the cast method, (3) the staining method. 

§ 1. I commence with the section method, remarking that most 
of my sections were made as described under (2). It is requisite 
that investigators should keep strictly to this method, otherwise 
they will not see the details of structure here described, or they will 
obtain from oblique sections images very difficult to interpret. We 
require very thin (e.g. 1/1000 mm.),* exactly transverse and longi- 
tudinal sections, whilst with Plewrosigma it does not matter if the 
direction of the cut deviates more or less from a right angle to the 
midrib. The transverse section of a valve of Pinnularia, if it has 
not touched the central nodule, has either the form of fig. 1 or fig. 2, 
plate VIII., except that in close proximity to the two ends the general 
form, by the disappearance of the rounded-off right angle, becomes 
semi-circular or semi-elliptical. In order to elucidate the change in 
the appearance of the mner structure we must remember that 
the surface image of Pinnularia exhibits coarse transverse striz, 
ending near the midrib, and which are regarded by Pfitzer and 
others as superficial furrows, and they have therefore been designated 
by various improper terms, such as furrows, surface sculpture, &c. In 
reality the outer surface, independently of the midrib, has neither 
elevations nor depressions, but is quite plane. If the section passes 
through the middle of a so-called furrow, it appears as in fig. 1 ; 
if it passes through the interspace, then it appears asin fig.2. The 
separate parts of the image are, as will be shown later on, to be 
explained as follows :—Hach so-called furrow is an inner chamber 
of the membrane, and, in proportion to the chambers of Plewrosigma, 
of enormous size, since it extends from the edge of the frustule to 
very near the midrib. Itis also of almost equal thickness through- 
out. But what is most remarkable is the fact that each chamber 
has a rather broad opening on the inner side of the cell-wall, by 
which it can be readily examined. The outlines of the opening are 
easily observed in the surface view, and have been often represented 
in the better class of illustrations (vide Pfitzer, 19, pl. 1, fig. 2). 
The draughtsmen, however, do not seem to have had a clear con- 
ception of the signification of these lines. Pinnularia is represented 
as a definite proof that the cell-envelope is broken through in the 
midrib, thereby allowing free exit to the protoplasm. All former 
reliable researches having apparently proved the non-existence of 
openings, and the endosmotic process having been generally accepted 
as the cause of movement (vide Naegeli, Von Siebold, W. Smith, 
Rabenhorst), Prof. Max Schultze (24) in 1865 put forward the 
opposite view and considered it proved that at the raphe of the 

* Sections as made by Pfitzer (19, p. 43) which are twice or thrice the thick- 


ness of a furrow, cannot, as a matter of course, be used for a delicate observation. 
At the best one recognizes only the general outline. 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 511 


diatoms there was a glutinous organic substance which could only 
be protoplasm. In 1870, Prof. Dippel’s work (3) appeared refuting 
Schultze’s view, and drawing attention to the fact that the mid- 
rib is not a cleft but rather a thickened line, having on the sides 
narrow longitudinal strie without perforations.* Then came 
Pfitzer’s work (19), who discovered the long-searched-for cleft and 
represented it so well that its existence is no longer doubted. He 
declares the detection of this cleft to be a task to be solved only 
with the highest powers, and draws a figure of a very narrow 
V-shaped opening through the thick envelope. Under existing 
circumstances it was of great interest to test Pfitzer’s statements. 
The conclusion I came to was to agree entirely, without reserve, 
with Dippel, and I must therefore deny the perforation of the 
cell-wall. This result cannot, however, be easily obtained. The 
number of more or less good transverse sections of Pinnularia 
I have is about 600; in most of them I actually observed in the 
midrib a fine transverse cleft. Its direction and its fineness are 
shown in figs. 1-3. They can be well seen with 300-400 where 
the section is good. With regard to direction I rarely see the 
cleft so V-shaped as drawn by Pfitzer; on the contrary, in most 
instances it commences on the outer surface at right angles to it. 
Then arise a great variety of changes in the appearance. We 
meet with sections in which it goes straight to the inner surface ; 
others where the vertical portion has a small hook turned 
inwards ; again, others where the portion facing the inner surface 
is obtuse to the vertical,—this case (not at all uncommon) is repre- 
sented in fig. 3. Such a change may be explained by a real 
difference in the object, which Schumann also quite correctly found 
with the surface view (23, p.73). A careful comparison of a great 
number of transverse sections, made according to method 2, will 
show in most cases the cleft going up to the inner side of the 
membrane. The question remains very doubtful whether the base 
is closed by a very thin envelope. After having made collodion 
casts, the image of the outer surface could be easily inter- 
preted; the fine cleft became filled with collodion, and in harden- 
ing a distinct midrib remains, almost exactly the same image as 
we see in the surface view. But the inner surface remained quite 
obscure. If a perforation of the membrane really exists, a similar 
midrib should be seen; but this is not the case. I have made 
a considerable number of such impressions, and not the slightest 
trace of a midrib could be seen, even with oblique light. 

These impressions fully convinced me that the fine cleft was 
closed at the base. That the transverse sections mostly show a 
fully developed perforation may be attributed to the following 

* This is what I proved simultaneously with Pleurosiyma (strie without 
spores). 


512 Transactions of the Society. 


cause :—In transferring a frustule to the gum it may, of course, 
be done according to method 2 without injury, but not always. 
In further experimenting the mass, in hardening, may suffer un- 
equal pressure on the valves, causing them to break, as also stated 
by Pfitzer (19, p. 50), and this is very likely to occur in the mid- 
rib. In this case they were injured before cutting. It is, how- 
ever, more probable that injury occurs during the cutting. The 
entire thickness of the silicified membrane adjoining the midrib 
is about 8-10 times as large as that of the fine envelope. As soon 
as the knife presses against this solid mass, the cap easily breaks 
off, which appearance is also observed with thicker masses at the 
central nodule crumbling out. In order to clear up this point I have 
made another series of sections according to method 1, in which 
injuries are more avoided. The best thereof show unmistakably 
at the base of the furrow this fine capping envelope exactly as 
represented in figs. 1-3. If the transverse section goes through 
the central nodule, the image then becomes as in fig. 4. Hence 
the nodule is also here a strong thickening of the midrib inwards ; 
outwards it has no distinction beyond that the middle line is 
broken and does not appear in the transverse section of the cleft. 
The membrane is flat. Here it should be noted that Schumann 
(23, p. 74) observed two focal images of this nodule in Pinnularia 
lata. Ihave seen them oftener in Pinnularia major. But they 
do not arise through a channel, as supposed by Schumann, but are 
produced by a depression in the centre of the nodule. This may 
often be seen without difficulty in a side view of the entire frustule. 
Similarly, the end nodules are inward projections. 

I will now proceed to the description of the longitudinal sec- 
tions. Their appearance must of necessity differ, depending upon 
whether the section goes through the openings of the chambers, 
or near the midrib, or near the edge of the frustule. Fig. 5 repre- 
sents a section through the chamber-openings showing the siliceous 
membrane with numerous long pegs projecting inwards in the 
frustule; these are the vertical partition-walls of the chambers. 

In fig. 6 we have a median longitudinal section ; the chamber- 
spaces appear like beautiful squares slightly rounded off in the wall- 
substance. The longitudinal section taken from the chamber- 
opening towards the edge shows hardly any difference from that 
last described. A vertical section along the midrib and through 
the central nodule has hardly any importance. If a longitudinal 
section goes a little obliquely towards the midrib, it shows in 
places the image in fig. 5, and in other places that of fig. 6. 
in all cages the outer limit of the cell-wall is perfectly straight 
throughout; nothing in the outline suggests furrows on the surface. 
From this representation it may well be supposed that transverse 
as well as longitudinal sections of Pinnularia are vexatious prepa- 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 5138 


rations in the hands of the tyro. In one and the same section he 
observes the most beautiful closed chambers and is fully convinced 
that my description of the Plewrosigma chambers is accurate. A 
few micro-millimetres further on he notices the magnificent pro- 
jections of the wall, not inferior to those of the epidermis or the 
vessels of higher plants, and with this he proves that I have erred 
in all points. If he follows Pfitzer’s advice with regard to breathing 
on the sections and thence obtains a mass of fragments, he will know 
neither what is outside nor what is inside the valve. For instance, 
if he turns round fig. 5 he will then see, according to his taste and 
intelligence, Pfitzer’s furrows on the outer surface, and then he 
confirms all Pfitzer’s fairy-tale. ‘Therefore I admonish every one 
to use the utmost precaution in interpreting the images ! 

§ 2. Collodion Casts.—For the technical process I refer to my 
former essay (6, pp. 489-90). These casts are of much greater 
importance with Pinnularia than with Pleurosigma; I can there- 
fore seriously recommend sceptics to try my experiments. The 
method is so easy in practice that even inexperienced manipulators, 
unable to do the cutting, will in this way obtain a general view of 
the details. It has been already observed that the chambers can 
be injected from the opening, so that in pouring fluid collodion on 
the inner side of the valves, it enters the opening and fills the 
chambers. With the evaporation of the ether the mass contracts, 
and after the collodion has hardened one sees the contents of the 
long cylindrical chamber shrivelled-up to a thread. The image 
takes the shape of the letter T. The vertical line is the collodion 
filling up the chamber-opening ; the horizontal is the collodion 
which fills the space of the chamber. If, therefore, the Pinnularia 
valve is taken away from the cast, these small T’s stand in military 
order in lines parallel to the midrib on the film. This T is 
mostly so elastic that without breaking it can be pulled out of the 
chamber. 

Fig. 7 is intended to bring clearly before the mind in a diagram- 
matic form what I have described above for a small portion of the 
cast; it is impossible to draw it exactly, because the interpretation 
chiefly depends on the alteration of the focus. With the lowering 
of the tube the horizontal T threads appear before the surface of 
the envelope is seen, and they disappear when the latter becomes 
visible. It is, of course, desirable always to examine for oneself such 
a cast. The central nodule leaves behind a pretty bold depression 
of elliptic shape. Sometimes are seen two small flat cavities 
adjoining each other, which also indicate the depression in the centre 
of the nodule (as above stated). Except the broken line in the 
middle, the collodion cast of the outer surface of a valve shows only 
a perfectly plane surface; but this line increases in distinctness 
near the central nodule and ends with a thickened point. This fact 


514 Transactions of the Society. 


implies that the cleft furrow is very deep, a fact which is also con- 
firmed by the transverse sections. This is simply the consequence 
of the gradual increase in thickness of the entire membrane, whilst 
the closing envelope is probably of even thickness. Closer obser- 
vation will show that the surface is not everywhere alike ; the area 
along the midrib, i. e. the portion free from chambers, appears quite 
plane ; the other, on the contrary, a little granulated, and occasion- 
ally one can even see a kind of glitter of chambers. In this case the 
cast teaches more than the longitudinal section, since it seems to 
display an unusually fine surface-difference which is not brought to 
the eye by the longitudinal section. Similar experiments were 
made with Pleurosigma. Asa matter of course, this condition of 
surface has nothing to do with transverse striz of Pinnularia. I am 
still in doubt whether this image is not called forth by the different 
evaporation processes above the chambers, therefore perhaps it may 
not correspond to any real difference between the valve surfaces. 
It is true that where air-bubbles are in the collodion the surface 
after hardening looks different from what it does when free of 
bubbles. 

Thus a complete and exhaustive explanation is given of all 
appearances of the surface image of a Pinnularia. In the imbed- 
ding of the valves in balsam, chamber and opening are filled with 
the strongly refractive substance and thus produce the coarse trans- 
verse striz. Hach stria is a chamber. 

§3. Staining Processes.—I cannot call these experiments more 
than tentative; they were intended, after I had recognized this 
most interesting condition of the chambers, to provide preparations 
in which the chamber-spaces alone should be filled with colour. 
The wall-substance, as is well known, does not take the staining. 
The experiments were made with solution of silver, picro-carmine, 
and Prussian blue; with the latter substance only I obtained pre- 
parations which were partially serviceable. The valves were put 
in aqueous solution of Prussian blue, poured off after some time, 
immersed in alcohol and constantly shaken to remove the blue 
which had deposited in and upon the valves. They were then put 
into balsam. In successful instances, not occurring frequently, the 
chamber is seen blue in the colourless wall. I have not persevered 
with these experiments. 

§ 4. Passing on now to the literature on Pinnularia sculpture, 
Schumann as far back as 1867 was approximately correct in his 
views. In his work (23, p. 73) he says that “in a fragment in 
partially reversed position the channels were most raised at the 
middle; each channel seems to consist of two vertical walls, the 
vault across being open towards the middle line.” On pl. IV., 
fig. 54, B, he exhibits such a fragment, from which one can imagine 
what he means. The real state of affairs could not be discovered 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 515 


by Schumann’s method ; it is therefore unnecessary to enter into 
the details of his statements. A considerable retrocession is found 
in Pfitzer’s works of 1869 and 1871 (18 and 19). In the former 
is briefly indicated that in Pinnularia we had to deal with smooth, 
narrow, elliptical spaces, concave outwards (pores = cost, Smith). 
In his second he substantiates this view by details. His views 
do not require special refutation ; they are wholly wrong. 

In my lecture (7) I first gave a correct representation of the 
real details, with preparations. It seems a pity that this lecture, 
referred to by Pfitzer (1873) in Just’s ‘ Jahresbericht’ (11, p. 28), 
did not give him occasion to make once more transverse sections 
of Pinnularia, for in all probability he would have been luckier. 
The most recent paper, however, which has come to my knowledge 
is a notice by Prof. Hallier, April 1882 (10, p. 156), according to 
which he holds a similar view with regard to the structure 
of the silicified membrane of Cymbella as Pfitzer expounded for 
Pinnularia. If this can be looked upon as a confirmation for 
Pinnularia, then I do not envy Prof. Pfitzer’s new triumph, which 
places Hallier’s reputation in an unfavourable light. 

Among the supporters of this unfortunate furrow-hypothesis 
seems to be Borscow, whose work I have not seen (vide Pfitzer, 
Just’s ‘ Jahresb.,’ 1873, p. 28). 

The literature as to the supposed perforation of the cell-wall 
along the middle line has been given above. I need only add 
that Pfitzer (19, pp. 175-80) has tried to dispose of Dippel’s 
objections to Schultze, and seems to have succeeded tolerably well 
in his so-called proof of the longitudinal cleft. But when he states 
that, in explaining the apparent movements, Dippel has put by far 
too great weight on the endosmotic processes, this objection falls 
to the ground, since Prof. Engelmann (4) has discovered a means 
in Bacteria to demonstrate the development of oxygen by diatoms 
under the Microscope, thereby furnishing the proof that the unseen 
gas-molecules escaping from the cell cause movement. Be this 
attraction or not of the Bacteria, these currents of gas, like enter- 
ing or flowing currents of water, must have such force that they 
can carry away a detached cell. 


2. Navieula. 


Of the numerous species, I have only examined the coarser 
striped Navicula lyra, Ehrb. The material was obtained from 
the mud gathered during the expedition of the “ Pomerania” (9). I 
chose a serial slide, on which were placed twenty-seven transverse 
sections through one valve. The lengths of the first and last sec- 
tions led me to anepone that three or four sections had already been 
made from the valve at either end, and by mischance are not on 


516 Transactions of the Society. 


the slide; consequently the sections are not all perfect, for a 
medium-size valve often contains more than sixty rows of dots. Be 
this as it may, several sections are excellent. From this I infer 
that the “lyra” figure is produced by thickened and chamberless 
portions of the cell-wall. In lke manner, the central nodule is a 
large flat thickening of the wall. Fig. 9 probably shows the sec- 
tion exactly through the middle of the valve (No. 13 of the series) ; 
fig. 10 section not far from the middle (No. 17 of the series) ; 
fig. 11 section not far from the end (No. 1 of the series). In the 
two last we see the thickenings, which I have designated as “ lyra 
plates,” clearly project inwards. The sculpture of the dotted portion 
of the valve may really be regarded as similar to Plewrosigma ; 
but here are clear rows of isolated chambers closed all round. 
Towards the edge the valves become thinner and the chambers 
smaller. The midrib with the chambers adjacent to it can only 
be seen faintly on most sections, especially the projection inwards 
is seldom distinct, and in the first section, fig. 11, is not seen. 
Longitudinal sections were not made; they probably would illus- 
trate the details more beautifully. Combiming with these results 
the surface view of a valve, fig. 12, we arrive at the conclusion 
that the doubts I formerly entertained (6, pp. 482-4) with regard 
to the existence of closed chambers, and of double membranes 
connected by column-like supports, are unfounded. The clearly 
separated spherules of the surface image also show separated 
chambers, and this is equally true of the entire series of rows. 
The space between such rows of dots, which is not rarely twice the 
breadth of the chamber diameter, represents without doubt the 
solid wall, which has not suffered a visible separation ; hence there 
is no communication between the separate rows. If we have thus 
before us the connecting link to Plewrosigma, it only requires 
another step to arrive at Pennularia: if the chambers forming one 
row are brought together a little closer and coalesce with each 
other, then we get the extended cylindrical chamber of the former. 
It is true that the large opening is unconnected. 


3. Plewrosigma. 


§ 1. Addenda to my former researches.—I add a few recently 
obtained results, chiefly due to the method subsequently learnt of 
placing the frustules in position and making serial sections (vide 
supra, “ Method of Investigation,” (1). 

(1) I was formerly obliged to neglect the transverse section of 
the central nodule (6, p. 478), because I could not find it; but in 
serial preparations of P. balticwm as well as P. angulatum, cut 
exactly transversely through a bundle, there is no difficulty in 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 517 


detecting it. In order to remain quite objective on this point with 
regard to the sculpture of Plewrosigma in general, I have made 
photographs of a number of transverse sections, and amongst these 
one of a central nodule of P. balticwm (French specimen, 6, p. 480). 
This shows without doubt that, as already proved by the cast 
process, the nodule is a solid thickening of the wall projecting 
inwards. 

(2) The Girdle-band was formerly described by me (6, p. 480, 
figs. 11 and 13) as a simple membrane. Pfitzer refuted this 
correctly (19, p. 20). In my present sections made exactly 
transverse to the median line, I see it sometimes single and some- 
times double, probably due to the close proximity of the two plates. 
If I gave no figures of this formerly, the reason was that in cases 
where it appeared double I concluded that accidentally with the 
imbedding in gum foreign matter adhered there, a supposition 
which might be excused by the fact of using only sections made 
through frustules lying pell-mell. 

(3) What I termed with P. baltiewm accessory rib (6, p. 481, 
and fig. 13), namely, a small second rib-like edge on the one side 
of the real median line, does not change position in all cases. For 
example, if it lies on the right of the main rib in one valve it will, 
as a rule, be seen in the other valve on the opposite side, that is, 
on the left. Exceptionally it may be found in both valves on the 
same side. Numerous experiments by crushing Plewrosigma valves 
under heavy pressure have taught me that, contrary to the former 
(6, p. 484) negative result, we can sometimes find fragments in 
which the one membrane is isolated, that is to say, it appears 
without any markings because the chamber-walls are rubbed off. 
This, however, is only found in a very narrow edge-portion of such 
fragments. Which membrane it is—whether the inner or the 
outer—cannot be determined as a matter of course. Mistakes with 
such fragments of uninjured valves, in which the markings are 
indistinct because the chambers are filled up with a glutinous 
substance, are avoided by convincing oneself of the much higher 
refraction of the valve in this case, whilst the isolated membrane is 
seen only very faintly. 

§ 2. Investigations by others.—(1) Pfitzer in his essay (19, 
p. 174) speaks of the sculpture of the cell-wall of Plewrosigma ; 
but since nothing new is mentioned, I refer on this subject to the 
General Remarks given in the third part of the present paper. 

(2) Miller has also studied the question, I had sent him a 
slide of Plewrosigma sections from the same gathering as the 
French specimen described in my original paper, and soon after I 
received from him two essays (14 and 15). As he was a novice in 
section-making who had occupied himself with coarse objects 
only, I treated his strange attacks with silence, in the hope 


518 Transactions of the Society. 


that an able observer would take up the matter and confirm my 
work, whereby I should have been relieved of the trouble of 
replying. In this hope I have for ten years been disappointed, 
and I am obliged now to refute Miller. 

T do not know whether Miller has made Plewrosigma sections 
according to my method, or whether his statements are made from 
examination of my own preparations. He says that my drawings 
are incorrect, especially that the diameter of the transverse section 
of the walls is proportionately much too thick, whilst the strong 
refractive thickenings at the ends of the same are not sufficiently 
given, hence he will not admit the existence of closed chambers 
(15, p. 621). 

With regard to this question, I have to reply that all my 
preparations of Plewrosigma were not only submitted to the late 
Max Schultze, and every doubtful and difficult point demonstrated 
before him by me personally, but that my diagrams were recognized 
by him as correct, and by his express desire my paper was com- 
municated to his ‘Archiv.’ This I mention without putting high 
value on the influence of mere authority. Next I refer to my own 
paper: on pp. 82-84 I discuss in considerable detail, with reference 
to the coarsely marked P. balticwm, the point as to the existence 
of columns between two envelopes or closed chambers. Nobody 
will infer from my description and diagram that I meant cylindrical 
columns or chamber-walls of equal thickness, nor that I intended 
to deny the thickenings at the ends. No such idea was in my 
mind. But if such end-thickenings do exist it is an understood 
thing that they are of pyramidal shape, the base towards the 
membrane, the point towards the space between the membranes, 
and they must operate as strong refracting bodies just like small 
convex lenses. On p. 511 I illustrate for this purpose the most 
striking comparison—the liver-wort leaf with large mesh-work. 
Choosing for study sections of a considerable thickness, and in 
which therefore two entire chambers might be found lying one 
over the other, then the effect is doubled; the two membranes 
will be seen more conspicuously projected from the inner space with 
the thinner walls. But such sections I did not select for my dia- 
grams, it being the rule, whenever the finest structural details were 
under investigation, to examine and to draw the thinnest sections 
or the extreme margin as the most reliable portion. In examining 
such sections one sees the detail exactly as I have represented it, 
and I must continue to assert that my diagram is true to nature. 

A second point of attack to be disposed of is Miiller’s idea that 
his flooding experiments (14, p. 75, and 15, p. 621) could not be 
brought into harmony with chambers closed from outside. I put 
entirely aside the value of such flooding for the elucidation of 
details of diatom structure. That all the fluids named by him 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 519 


will penetrate the interstitial molecules of thin membranes with the 
greatest facility is known to every novice. Were one to suppose 
or to search for holes with this experiment we should cancel every 
investigation made during a century with regard to endosmose. 
This point needs no refutation. I refer to what I said, pp. 487-8, 
about the penetration of water into the valves, and it will be the 
same with all other fluids. The further deductions by Miller, 
pp. 622-5, in connection with his flooding experiments are by far too 
obscure for me. Even admitting the facts with regard to Pleuro- 
sigma were as Miiller believes, that the chamber had an opening 
outwards as with Triceratiwm, there is no reason whatever to 
infer that the microscopical surface-image could be altered in air, 
balsam, bisulphide of carbon, &c.. The chambers whether elliptical 
or spherical in connection with the wall-nodule operate in the 
one case as concave lenses, in the other as convex lenses; whether 
they have an entrance from outside or not is immaterial. ‘If en- 
trances do exist, but which up to the present have not been 
observed, I would sooner admit that they lie on the inner side of 
the membrane. In support of this statement is the analogy of 
Pinnularia and the collodion cast showing a delicate relief-image 
of the inner side (6, p. 493). 

(8) Miller seems to think (14, p. 76) that we ought to in- 
vestigate the real condition of diatom structure indirectly, and 
especially the Plewrosigma sculpture, and in illustration he 
describes his investigation of Triceratiwm favus. On pp. 79-80 
he has no hesitation in applying to Plewrosigma what he found 
with Triceratium. This means, in other words, that everything 
said by Flogel withi regard to Plewrosigma does not quite agree 
with what I (Miller) found out with Triceratiwm, therefore the 
former must be wrong ! 

(4) The fourth point is Miller’s representation of a transverse 
section of Plewrosigma (15, fig. 1aand1b). He writes (p. 637) 
that he succeeded in finding it amongst numerous sections, and 
then he terms it (p. 621, and explanation of fig. on p. 641) 
P. scalprum, with a sign of interrogation. What he has repre- 
sented there is a fragment of a very thick transverse section of 
P. balticwm! I cannot ayoid calling this a prodigious blunder. 
For Miiller, after his researches with diatoms, ought to know that 
the small delicate P. scalprwm could never furnish such a colossal 
transverse section, in whatever direction made. Further, on 
p- 488, fig. 19, 1 have described and figured the transverse section 
of P. scalprwm, and the fig. is on the same scale as the transverse 
section of P. balticwm, fig. 13. A confusion between these two is 
utterly impossible, 


520 Transactions of the Society. 


4, Surirella. 


In avery primitive form Rabenhorst, 1864 (22, p. 9, fig. 12 d), 
gave a transverse section of Surirella. It is rectangular, with short 
straight lines at the corners. The sculpture of the valve was 
minutely described by Pfitzer (19, pp. 108-10, pl. I., figs. 8-10, 
pl. V.), and the former researches by Smith and Focke were con- 
sidered. About the finer sculpture which produces the transverse 
and longitudinal striz Pfitzer said nothing. The representation 
of the coarser details may serve as a model, and I shall refer to it 
frequently. The only species closely examined by me occurs in 
fresh water, and I believe it to be S. biseriata, Ehrenb. The 
minute drawing on the surface is like the well-known test-object 
S. gemma. From a single valve of this species I made a series of 
transverse sections, from another a series of longitudinal sections, 
and lastly a collodion cast of the inner side of a valve. 

The general outline of the valve, best seen from the cast, is 
an elongated oval almost like a lancet. In the middle lengthways 
is a ridge, on the margins are the wings as described by Pfitzer in 
S. calcarata (19, pl. L., figs. 8-9, pl. V., fig. 6). The surface 
between the middle line occupying the highest edge of the ridge 
and the wings is bent somewhat wave-like. The wings are not 
simple membranes, but are double, a fact already established by 
Focke and Pfitzer. They are really folds in the cell-wall. Both 
membranes adjoin closely in some places; in certain intervening 
spaces corresponding to the waves on the surface they are not 
close together, but show a tube-like space. All these communica- 
tions end in a delicate continuous tube, which forms the tip of the 
wing. 

‘The diagram of Surirella consists of (1) a midrib without 
nodule or any other distinction ; (2) numerous transverse ribs which 
extend at pretty regular distances from the midrib towards the 
edges ; (3) transverse lines between these ribs and perfectly parallel 
to them ; (4) longitudinal lines of extreme delicacy which cut the 
transverse lines at right angles. We will now examine the result 
of the transverse sections. The transverse section series com- 
mences with a section the shape of which suggests that three or 
four had been taken before; the last, No. 66, has had at least ten 
successors of equal thickness. From these facts we may appreciate 
the delicacy and extreme usefulness of thisseries. Fifty times over 
these sections substantiate the correctness of Pfitzer’s images. I 
have drawn Nos. 2, 9, 39, 40, and 66. Of the longitudinal section 
series I draw only the first, pl. IX., fig. 18, and another, fig. 19, 
which goes through the middle of one valve, and is the most 
instructive, as it shows most distinctly the waves on the sur- 
face. My longitudinal section series has not that technical 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 521 


perfection which distinguishes my transverse sections, although 
it shows nearly all one can reasonably expect. Putting trans- 
verse and longitudinal sections together, one readily sees that the 
former must look a little different when they are cut through the 
elevations or when through depressions. Pfitzer has already drawn 
attention to this fact, and as far as I can judge he has deduced it 
from the optical transverse sections of the raised frustules (p. 109). 
The real transverse sections confirm his view. It is not uncommon 
that the section is so thick, that lying at the declining edge of a 
wave its outlines in the upper part differ from those in the lower. 
Figs. 13, 15, and 16 illustrate this by finely drawn lines. These 
are differences which occur with the transverse section of the 
wings. The section goes either through a place where the mem- 
branes holding together the wing lie closely one upon another, 
exhibiting the image fig. 14; or else it goes through the inter- 
vening space, then the wing looks like a flat-pressed smooth 
surface having a lumen in open communication with the cell 
(fig. 15). In the former case one observes at the highest margin of 
the wing the transverse section of the extremely thin tube above 
mentioned. Pfitzer (vide p. 110) has expressed the opinion that along 
the entire wing-margin runs a fine cleft, or that there exist a large 
number of extremely small openings standing in one line. This 
cannot be taken for more than a mere opinion. My transverse 
sections in no way corroborate this opinion; on the contrary, they 
show these fine marginal tubes closed everywhere outwards. These 
details can be best understood by comparing it with the surface view 
of the wing, fig. 18. By comparing the figured transverse sections 
together it will be seen that the proportion of the size of the 
wing to the surface towards the end is different from what it is in the 
middle of the valve. We see further that there is a difference in 
the curvature of the surface of the valve, about which more further 
on. With regard to the finer sculpture, the transverse sections 
exhibit the midrib as an irregular thickening; one sees there a. 
point. However, the membrane in its whole extent is so extremely 
delicate (the measures give 0°4—0°5 yw, even this is too high) that 
it becomes very difficult to distinguish differences of thickness. 
Transverse ribs are delineated in the longitudinal section (figs. 19 
and 20) clearly like small ovals on the crests of the waves, and these 
ovals are mostly more pointed whilst the valleys are rounded. I 
see the transverse strice in the delicate longitudinal sections as clear 
pearl-like punctures, as in fig. 20. No rib-like projection can be . 
observed, however, for the shadow permeates the whole mass so 
that it must necessarily be caused ina manner similar to Plewrosigma. 
The longitudinal strize I could not perceive with the desired clear- 
ness in the thinnest transverse sections, not even with oblique 
light. Sometimes I observed a kind of glimmer, but nothing 
Ser. 2,—Vot. LV. Qn 


522 Transactions of the Society. 


beyond this. With central light the transverse sections appear 
homogeneous, and flat on both sides. In examining the sections 
I could not trace differences in the membrane thickness ; nor did I 
observe projections or continuations with one exception near the 
edge of the valve outside the wing, and this occurs pretty constantly 
and may stand in connection with the attachment of the girdle-band. 
On this matter I cannot give more definite explanations. If we exa- 
mine the cast in view of these facts, the wave shape of the surface is 
thereby substantiated ; it follows that the fluid collodion must have 
entered into the tube-system of the wings, and in pulling off the 
valve there must have been left behind contracted tubes. In 
reality, not far from the edge, such protuberances of collodion are 
seen at regular intervals. The cast shows absolutely nothing of 
the transverse strize however oblique may be the illumination with 
which it is examined. From the above we infer, with regard to 
the finer sculpture, that midrib and transverse rib are both wall- 
thickenings of which the transverse striae have probably been 
produced by the cylindrical hollow spaces within the membrane. 
Small hollows of these cylinders then suggest an appearance of 
longitudinal lines, and the condition is similar to the transition of the 
simply striped Pinnularia to the pointed striped Navicula. This 
lesser definition remains obscure. For microscopists these investi- 
gations about Surirella sculpture are of some importance, since they 
explain various peculiarities of S. gemma which may be looked upon 
as similar to S. biseriata. At first sight the longitudinal section, 
fig. 19, teaches us that it really is no brilliant performance for an 
objective when it shows the much-spoken-of longitudinal striz every- 
where at the same time. All that is proved is that the objective 
possesses the power of showing at the same not only striz which 
are within the focus but others which are beyond. This can be 
easily obtained with bright sunlight, but with ordinary day- 
light an objective should only show clearly either the striz on the 
elevations or those on the depressions. Secondly, the transverse 
section near the end, fig. 14, establishes the fact that in order to see 
both strize at the same time it is best to examine the end portions of 
a valve under an obliquity of illumination of 45° to both directions. 
Here the surface of the valve is smoother. Altogether Surirella, 
on account of its uneven surface, is a very unsatisfactory test-object. 


(To be continued.) 


XIL.—On a New Microtome. 


By C. Hinton Goxipine-Birp. 
(Read 14th May, 1884.) 


Tue necessity for providing some instrument which offered the 
advantages of modern-microtomes and yet was within the reach of 
those whose work being of intermittent character did not warrant 
their employing the somewhat elaborate instruments that are 
found in laboratories, made me originate the instrument shown in 
figs. 83 and 84. 

The microtome is intended to be held in the hand during use, 
and is of two forms—one for ice and salt, the other for ether. 
The former (fig. 83) consists of a cylindrical vulcanite chamber 
closed at the bottom by a brass screw-lid, and at the top by a 


Fig. 83. 


i 


«ie 


- 


| + 


| A 


‘ih 


il 
] 
iN 


disk of vulcanite, having in the centre a plate of brass (freezing 
plate) 7/8 in. in diameter, and terminating in the chamber by 
a rod of brass. A metal cap surmounted by a glass plate and 
pierced in the centre to allow the freezing plate to project, screws 
over the upper end of the cylinder, the outer surface of which 
bears a male screw of hard metal on which the cap turns. As the 
cap is turned round a spring catch clicks at given intervals; these 
are so arranged that as the cap rotates from left to right each 
click shows that it has sunk on to the cylinder 1/1000 in. ; hence 
any tissue fixed on the freezing plate projects, at each click, 
1/1000 in. through the hole in the glass plate of the cap, and a 
2N 


524 Transactions of the Society. 


razor now passed over the latter cuts off a section of the same 
thickness. By turning the cap through half an interval, sections 
of half that thickness may be obtained. To fix the specimen it is 
only necessary to fill the cylinder with ice and salt, the specimen 
being previously prepared in gum, according to the general rule 
when freezing is employed as the means of imbedding. 

The form in which ether is the freezing agent employed 
(fig. 84) differs mainly in the fact, that the lower half of the cylinder 
is a chamber for holding the ether, with the two nozzles that give 
the necessary jet. The freezing plate, cap, and regulating apparatus 
are the same as in the ice and salt machine. Mr. Swift (to whose 
skill and ingenuity the details of manufacture are due) has intro- 
duced a very ingenious but yet simple means whereby some of the 
ether can be saved from the spray ; much must of course escape, 
but much also falls back on to the jets again (since the spray is 
a vertical one); this portion impinges on to a funnel-shaped 
diaphragm, which acts as a lid to the ether chamber, and through 
which, by means of a minute opening, it again finds its way back 
to the ether chamber. 

For those who, like myself, have to work for a large histo- 
logical class, there is nothing equal to the Groves-Williams ether 
microtome in the laboratory: but for intermittent and home work ~ 
I believe that the form of instrument that I present to-night, 
leaves scarcely anything to be desired in accuracy of work, simplicity, 
convenience, and portability. 


XUI.—On some Appearances in the Blood of Vertebrated Animals 
with reference to the ocewrrence of Bacteria therein. 


By G. F. Dowpzswett, M.A., F.R.MS., &e. 
(Read 11th June, 1884.) 


THE occurrence normally, of micro-organisms in the bloéd and 
tissues of healthy animals, has been the subject of many observa- 
tions, in some instances with contradictory results. It is, however, 
now well established that, both in man and other animals, they 
are constantly present in certain situations, not only in the 
mouth and lower intestine, but in some cases at least, in the liver 
and pancreas; on the other hand it has been shown that in the 
blood they are not usually present in a state of health. ‘To deter- 
mine this latter point microscopical examination is inadequate, inas- 
much as mere negative observations are inconclusive, and the ques- 
tion has been decided by physiological experiment, viz. by taking 
blood from the heart or vessels, with precautions against contami- 
nation, when it is found that it may be preserved indefinitely, free 
from septic changes; and even in some instances, as has been 
demonstrated in King’s College by Professor Lister, without 
coagulation. 

In some pathological conditions—in certain infective diseases, 
—as is now well known, micro-organisms are found constantly 
present in the blood, and in a few cases are shown to constitute the 
true contagium, the actual materies morbi. It is possible too, that 
in other conditions not yet investigated —as for instance in a tem- 
porary access of fever—they may appear here, starting from those 
situations in which they are normally present, and again shortly 
disappear. For the determination of the question of their occur- 
rence in these situations, it is essential that such other bodies as 
may be, and have been, in some instances mistaken for them, should 
be well known. 

The appearances in the blood which I have to record to-night 
have been already described by myself or others, and I have but 
little that is new on the subject now to offer. Mistakes, how- 
ever, that have been made—in one case in a report published quite 
recently—show that these phenomena are by no means generally 
known or recognized. 

1. Max Schultze’s Corpuscles.—The first instance to be here 
mentioned is, that in the blood of man and many animals, besides 
the red and white corpuscles there are present normally, though 
in very variable numbers, small corpuscular bodies, the nature of 
which has been the subject of great diversity of opinion, and is 
far from being as yet determined. These are known as Max 


526 Transactions of the Society. 


Schultze’s corpuscles, so-called from their first observer. The 
most careful investigation of these is that by a Fellow of this 
Society, Dr. Osler,* who has given a full description of them, 
with drawings. He observed them both within the blood-vessels 
and in preparations on the slide under the Microscope, but he leaves 
their nature and function quite undetermined, though his observa- 
tions are valuable, inasmuch as he showed that whereas in 
preparations under the Microscope they are found in masses, 
within the blood-vessels they occur singly, isolated forms being 
distributed throughout the blood-plasma. Though their appearance 
should be familiar to every student of histology, they have un- 
doubtedly often been mistaken for Bacteria, as obviously is the case 
in the recent report of one of the most important investigations 
of the day, to which I have just referred—a circumstance 
which fully justifies their careful examination and description in 
this relation. In size they are very variable, from half the diameter 
of a red corpuscle to very much less. In shape many are spherical 
or discoid, some pyriform, or more exactly, shaped like a comma, 
or spermatozoon-like, as Osler terms them; others quite irregular. 
Some appear distinctly coloured as the red corpuscles, though paler, 
from their smaller size or thickness. 

I have made frequent and prolonged examination of these 
bodies, and can state from my own observations, that they are not 
independent organisms or microphytes, as has been supposed, and 
I believe that. a large portion of them at least, are mere débris, 
disintegrated red corpuscles; they may be indefinitely increased in 
numbers, with identically similar forms, by treating a preparation of 
blood on the slide with a 10 per cent. solution of sulphuric acid ; 
though somewhat strangely, this has been stated to be a good 
preservative fluid for the red corpuscles. 

It has been shown by Riess that they have a pathological 
significance, in so far that they vary in number in different states 
of health; it also seems to me that they increase and diminish at 
certain periods of the day, as do the white corpuscles; both these 
conditions agree with the view that they are disintegration products ; 
and if this be so, their numbers would probably be enormously 
increased in cholera and similar wasting diseases, in the abnormally 
active metabolism of the tissues. On the other hand, however, 
they appear to have been regarded by some as representing an 
early stage of the development of the red corpuscles, the so-termed 
hematoblasts, but the description of these is so vague that it is 
difficult to arrive at any conclusion respecting them. 

It. appears to me, however, that in many cases in the descrip- 
tions of these corpuscles hitherto published, bodies of two different 
characters have been classed together, the one of regular discoidal 


* Pyoc. Roy. Soc., xxii. (1874) pp. 391-8, and Mon, Mier. Journ., 1874. 


On some Appearances, &c. By G. F. Dowdeswell. 527 


or spherical form, very variable in size, from the most minute up 
to nearly half that of a red blood-corpuscle ; these appear to be 
the blood-plates of Bizzozero, and very possibly have an evolutional 
significance: those of the other class, which more particularly relate 
to the present subject, are always comparatively small, and more or 
less irregular in form as above described. 

Though the bodies here in question—Max Schultze’s cor- 
puscles—are not mentioned in many treatises on microscopic 
anatomy, yet as they appear to be always present in varying 
numbers in the blood, whether they are evolutional or involu- 
tional forms, they must be regarded as part of its normal 
constituents ; and with respect to the subject here under con- 
sideration, viz. investigation of the micro-organisms which occur in 
these situations, must not be overlooked. ‘The occurrence of the 
mistake I have mentioned, which shows that they are not always 
well known, where pre-eminently they ought to be so, has induced 
me to refer to these bodies at some length. 

2. Proteid or Addison’s processes of the ved corpuscles.—The 
next appearances which I have to mention, resemble Bacteria 
far more closely than the former, indeed morphologically they are 
indistinguishable from them; they have been described by several 
writers independently, in many cases apparently without knowing 
what had been observed by others. In general, in a preparation of 
blood under the Microscope, they appear first as small protuberances 
or bud-like processes on the surface of the red corpuscles, very 
similar to the first stage of gemmation in a yeast-cell; these some- 
times develope—as when the preparation is treated with a 5 per cent. 
solution of ammonium chromate—to broad pseudopodial processes, 
in some cases of comparatively considerable dimensions; at other 
times they form long fine filaments, apparently continuous, unseg- 
mented, three omfour times in length the diameter of the corpuscle, 
of variable thickness, but frequently so fine as to be with difficulty 
recognizable with the highest powers of the Microscope; at other 
times they form rosaries of minute spherules, similar to the torula 
form of micrococci, or the spores of Penicillium. In general they 
very shortly become detached from the parent corpuscle, and may 
then be observed free in molecular movement in the field of view, 
simulating exactly Micrococci, Bacteria, or Bacilli; at other times 
they are retracted within the plasma of the parent corpuscle. I 
have previously regarded this occurrence as due to the spontaneous 
contractility of the substance of the red-corpuscles, thereby shown 
to be protoplasmic ; but I must here qualify that opinion, inasmuch 
as it has lately been demonstrated in a very ingenious experiment, 
by Haycraft, of Edinburgh,* that egg albumen, inclosed in an 
indiarubber ball perforated with minute apertures, and placed in a 


* Proc. Roy. Soc, Edin., 1880-1, p. 29. 


528 Transactions of the Society. 


neutral solution of suitable specific gravity, upon the ball being 
pressed will throw out filamentous processes, which are retracted 
on the ball again expanding, showing that such processes are not 
necessarily protoplasmic; they, however, demonstrate another 
point in the constitution of the red corpuscles, viz. that they have 
no true cell-wall or membrane, as has been sometimes supposed. 

These appearances were first described and figured in the Quart. 
Journ. Micr. Sci. for 1861, by the late Dr. William Addison, F.R.S., 
and after him may be appropriately termed Addison’s processes. 
He induced them by treating blood on the warm stage with a 
solution of sherry and salt solution or quinine; they may also be 
produced by many other reagents and conditions, as I have previously 
described in the same journal, 1881, where I have collated the 
previous observations upon them. They are readily produced 
by solutions of septic matter, and I have frequently observed 
their occurrence spontaneously—that is without the addition of 
reagents—in the blood of septichzemia examined under the Micro- 
scope, where they have also been observed by others, but without 
apparently recognizing their nature. In the report of the French 
Cholera Commission in Egypt just published,* filamentous processes 
from the red corpuscles of the blood kept in the incubator for 
some days} are recorded, but without further observations upon 
them. ‘They probably occur also in many other pathological condi- 
tions. They are produced by heat, as described and figured by 
Dr. Beale and by Max Schultze, through a mere disintegrating 
action; also by treatment with gas, as recorded and figured by 
Professor E. Ray Lankester. In the blood of the frog they occur 
conspicuously, and are more readily produced there than in the 
higher animals. The appearances herein have been described in 
sensational terms by some German writers, but so vaguely that it 
is impossible to be certain what is intended, whether these pro- 
cesses of the red corpuscles or true micro-parasites, one form of 
which has been fully described by Professor Lankester ; others are 
said to occur frequently at certain seasons, but I have not been 
able to confirm this latter observation. 

These processes when detached from the parent corpuscle, are 
not, as | have said, to be distinguished morphologically from Bac- 
teria, and their behaviour to micro-chemical reagents is difficult 
to observe, from the impossibility of keeping these minute bodies 
within the field of view. Upon and during such treatment they 
are not appreciably swelled or decolorized by water, as are the 
red or white corpuscles; nor is the action of acids or of alkalis 
much more apparent; they may, however, be distinguished from 

* “Archives de Physiologie Normale et Pathologique,’ 1884, p. 411. 


+ And others after a longer interval, at the temperature of the air (Lostorfer’s 
corpuscles ?). 


On some Appearances, de. By G. F. Dowdeswell. 529 


Bacteria by their behaviour with the anilin dyes, by which, as by 
methyl-anilin-violet, they are only stained faintly, like the red 
corpuscles, while all forms of Bacteria, with a very few exceptions, 
are readily and deeply coloured by this salt. Since the publication 
of my own account of these bodies, their formation by the action of 
some reagents has been observed and described by Dr. Stirling,* 
and most recently in the blood in cholera as mentioned above. 

Conclusion.—Thus it is seen that there are several appearances in 
the blood which may readily be mistaken for micro-parasites—to 
use acomprehensive term—though the occurrence of the latter is 
probably more frequent in abnormal and pathological conditions 
than yet recorded. The increasing importance of this subject renders 
it desirable that every observer should be familiar with these 
appearances. I pass over here coagula, granules, and pigment, which 
frequently occur in blood, the external form of which, if carefully 
observed, sufficiently distinguishes them from the cells of living 
organisms. 

But while, on the one hand, other bodies are mistaken for 
Bacteria, in some cases veritable forms of the latter have been asserted 
to be but fibrinous coagula, or in another case mere organic 
crystals. 

Apart from the subject of pathological appearances and the 
occurrence of foreign or parasitical bodies in it, the normal 
form elements of the blood, after the observations of nearly 
two centuries, are far from being exhaustively known; the 
varieties of the white corpuscles, of which there are several, 
have been little more than suggested; some phases in the evolu- 
tion of the red corpuscles, as is asserted, have been but very recently 
observed; whilst the functions, origin, and destination of Max 
Schultze’s corpuscles are scarcely more than conjecture: and 
whilst, on the one hand, the micro-parasites of the blood, its 
abnormal or pathological features, furnish a subject for examination 
with, and an excellent test for, the highest powers of the Micro- 
scope, its normal characters offer a field of investigation for 
moderate powers, with a prospect of most valuable results, one that 
is always readily available, but which has hitherto been somewhat 
neglected by microscopists generally. 


* Journ. Anat. and Physiol., 1883. 


530 Transactions of the Society. 


XIV.—On Protospongia pedicellata, a new compound 
Infusorian. 


By Freprerick Oxury, F.R.M.S. 
(Read 11th June, 1884..) 


Tuts interesting organism was first discovered by me in a pond near 
Snaresbrook, Essex, in the spring of the year 1882. I was search- 
ing the numerous ponds in that neighbourhood for Voluox globator, 
and happened to dip a bottle amongst some rushes in a quiet 
corner, which appeared to be a likely place to find what I was 
looking for. On holding the bottle up to the light I observed in 
it a number of minute flocculent bodies, the nature of which I could 
not determine with a pocket-lens, and therefore carried them home 
for further examination. 

With the Microscope I found them to consist of colonies of 
monads possessing collars and flagella, and connected together in 
vast numbers and in rather close proximity to one another on the 
periphery of some exceedingly transparent hyaline substance. _ 

Being out of health, and, moreover, having only a very slight 
acquaintance with the group of Choano-flagellata, derived from Mr. 
Saville Kent’s papers in the ‘Popular Science Review’ and 
‘Monthly Microscopical Journal,’ and from some specimens shown 
me by my friend Mr. Charles Thomas, of Buckhurst Hill, I did 
not at that time recognize that any new discovery had been made, but 
I gave some specimens to Mr. Thomas which we examined toge- 
ther, and also spoke of them to another microscopical friend, 
Mr. C. Livingston, who resides near the pond out of which they 
had been obtained. 

In the spring of the present year, 1884, I again visited the 
pond in company with Mr. Livingston and Mr. Thomas, and there 
found the organism again in greatabundance. Mr. Livingston took 
great interest in the little creatures and examined them under very 
high powers, and made measurements and computations from which 
it appeared that the bodies of the individual monads are from the 
1/3000 to the 1/2500 of an in. in length, the collars when ex- 
tended being about twice, and the flagella five to seven times the 
length of the bodies, and that the number of individuals composing 
a colony amounted to from 10,000 to 20,000 or more. Mr. 
Livingston was not able from Kent’s ‘ Manual of the Infusoria’ to 
identify the species, the nearest approach to it appearing to be 
that described by Mr. Kent under the name of Protospongia 
Hicker. Ue therefore sent Mr. Kent some specimens for identi- 
fication. Mr. Kent considered the specimens undoubtedly new, and 
interesting to him as tending to support the conclusion he had arrived 


On Protospongia pedicellata. By Frederick Oxley. 531 


at as to the relationship between the Infusoria and the sponges, but 
being on the eve of his departure for Tasmania he was unable to 
pursue the subject. Mr. Kent also pointed out the fact, which my 
friends’ and my own observations have since confirmed, that each 
individual monad is furnished with a short pedicel or footstalk by 
which it is held in position in the zoocytium, this footstalk, accord- 
ing to Mr. Livingston’s measurement, being about the 1/10,000 of 
an in. in length. 

Specimens, accompanied by a short description, were sent to 
Herr von Stein, who gathered from the description that the 
species was new; but the specimens themselves were lost in the 
post. A specimen mounted with osmic acid has, however, since 
been sent, which has enabled him to confirm his opinion. 

The drought we have experienced for some weeks past has so 
dried up the pond from which my specimens were obtained, that no 
more are to be had at present, and I have not therefore been able to 
satisfy myself that Protospongia pedicellata agrees in all points 
with Mr. Kent’s description of the genus; but so far as my obser- 


Fic. 85. Fig. 86. 


vations have extended, it differs from P. Hackeli 
in the possession of a footstalk and in the num- 
ber of individuals comprised in a colony, fifty or 
sixty only being the number assigned by Mr. 
Kent to P. Hackeli, whilst I have not met with 
any colony of P. pedicellata that did not contain 
a thousand or more. 

I am indebted to Mr. Thomas for the 
drawing accompanying this paper (fig. 85), 
which is an attempt to represent the appear- 
ance of a moderate sized colony as viewed by a 2/3 in. objective 
with A eye-piece, but no drawing can give an adequate idea of the 
beauty of the organism when illuminated by the paraboloid and 
displaying its thousands of flagella in active vibration causing the 
entire colony to sail slowly about the field of view. Fig. 86 repre- 
sents an individual monad very highly magnified showing the 
footstalk. 


532 Transactions of the Society. 


The collars are of course not seen in these circumstances, as 
they require a high power to observe them properly, but after 
haying been seen and studied under a 1/16 they are easily recog- 
nized with a 1/4 in. or even a 2/3 under favourable circumstances 
of illumination. ‘The mucilaginous zoocytium can only be seen 
with difficulty owing to its extreme transparency and freedom 
from foreign particles, and is best distinguished under black-ground 
illumination with a low power. 

The shape of the colonies is usually more rounded than that 
of the specimen from which Mr. Thomas’s drawing was taken, 
sometimes approaching a spherical form, but always presenting 
indications of having been attached to some other body. They 
probably grow on the stems of rushes, &c., but attached so slightly 
as to be easily displaced when the water is agitated by dipping a 
bottle, mouth downwards, amongst the rushes, moving it about 
a little and then suddenly reversing it, taking care not to stir up 
the mud from the bottom of the pond. 


(5385) 


XV.—On a New Form of Polarizing Prism. 
By C. D. Anrens. 
(Read 11th June, 1884.) 


Tue prism which I desire to bring to the notice of the Society is 
intended for use either as a polarizer or an analyser. It will, I 
hope, be found especially useful as an analyser for the Microscope. 

The employment of a Nicol prism above the eye-lens is 
subject to the great inconvenience that, owing to the necessary 
length of the prism, the eye of an observer is so far removed 
from the lens that a portion of the field is cut off. Double-image 
prisms of the usual construction are shorter, but they have another 
defect, viz. that the angular separation of the rays is so slight 
that the eye sees both images at once, and some confusion is thus 
caused. 

My object in constructing this improved prism has been to 
obtain a much wider separation of the two beams of light; so 
that one of them, although not actually removed entirely by total 
reflection (as in the Nicol prism), is so far refracted to one side 
that it may be neglected altogether. I made several attempts to 
construct such a prism some years ago, but failed (as probably 
others have done) owing to the difficulty or impossibility of avoid- 
ing distortion and colour, and of obtaining a wide separation of the 
ordinary and extraordinary rays in a prism made up of only two 
pieces of Iceland spar. 

I have now effected the desired object by making the prism of 
three wedges of spar cemented together by Canada 
balsam, as shown in the accompanying drawing (fig.87). Fa. 87. 
The optic axis in the two outer wedges is parallel to 
the refracting edge, while in the middle wedge it is 


G 
perpendicular to the refracting edge, and lies in a 
plane bisecting the refracting angle. This disposition 
of the optic axis is the one originally suggested by 
Dr. Wollaston, and has the effect of causing a greater 
angular separation of the rays than Rochon’s construc- 
tion. By the employment of three prisms instead of 
two I am able to give the middle prism a very large 
angle, and yet to correct the deviation of the rays so far 
that on emergence they make approximately equal angles with the 
central line of the combination. 

Nearly in contact with one of the terminal faces of the prism 
I place a prism of dense glass of such an angle that it just corrects 
the deviation of one of the rays and also achromatizes it, while it 
increases the deviation of the other ray to such an extent that it 


t 


b 
e 


~ 


o4. Transactions of the Society. 


may be practically disregarded altogether; an eye, even when 
placed almost close to the prism, receiving only the direct beam. 
This beam is, of course, perfectly polarized in one plane, and can 
by a proper arrangement of the glass compensator be rendered 
practically free from distortion and colour. 

Other methods of effecting the compensation have suggested 
themselves in the course of my work, and I have obtained the 
best results by adopting the arrangement represented in fig. 88. 

In this, the glass compensating prism, instead of being 


Fic. 88. | mounted separately, is cemented upon one of the 
terminal faces of the compound spar-prism ; the angle 
G of this latter, and also of the other terminal face, being 


suitably modified. 

This seems distinctly preferable to the original 
arrangement, for several reasons. 

1, The total length of the compound prism is 
rather less, being scarcely more than twice its breadth. 

2. The field is rather larger, so that the prism can 
be used over deeper Microscope eye-pieces (A and B) 
without any of the field of view being cut off. 

3. The whole arrangement is more compact, all the compo- 
nents being firmly cemented together, and therefore not liable to 
accidental displacement. 

4, There is less loss of light by reflection, the reflecting surfaces 
being reduced to two. 

A ray of light entering the prism in a direction parallel to its 
axis is divided into two rays; one of which, on emergence, follows 
a course parallel to that of the original incident ray, and is practi- 
cally free from distortion and colour: the other ray is deviated to 
the extent of about 59° 30' (for yellow sodium light), being, of 
course, strongly coloured and distorted. The angular separation 
is so great that this latter ray does not interfere with ordinary 
observations. 

I hope that the prism, which has cost me much time and labour, 
will meet with the approval of the Society, and take a place as a 
useful accessory to the Microscope and other optical instruments. 


SUMMARY 


OF CURRENT RESEARCHES RELATING TO 


AO b6G Y AND BOTANY 


(principally Invertebrata and Cryptogamia), 


MICROSCOPY, &c., 


INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* 


ZOOLOGY. 


A. GENERAL, including Embryology and Histology 
of the Vertebrata. 


Polar Globules and other Elements eliminated from the 
Ovum.}—In this important contribution to the theory of sexuality, 
A. Sabatier sums up our knowledge as to the phenomena of sperma- 
togenesis :— 

A cellular element belonging to the so-called male gland (and not 
specially an epithelial cell) grows and acquires a thicker zone of 
protoplasm ; this first differentiation gives rise to the primitive re- 
productive cell; this cell multiplies by division of the nucleus and 
of the protoplasm ; the resulting agglomeration or group of cells is 
that which forms the male tubes of Pfliiger, or the polyblasts. The 
first generation of cells (protospermoblasts) becomes more or less 
independent, and gives rise to one or more generations of protospermo- 
blasts. 

Later on, each cellular element, which is definitively male, 
acquires a thicker “atmosphere of protoplasm,’ while in the zone 
which is in direct contact with the nucleus there arise, by concentra- 
tion and differentiation, that is to say by true genesis, homogeneous 
hyaline corpuscles, which undergo a further differentiation, and 
may multiply by simple division. These corpuscles, once formed, 
take a centrifugal direction, pass to the periphery of the cell, and 
become converted into spermatozoa. In this way is formed the 
deutopolyblast, at the surface of which the deutospermoblasts are 
eliminated. 


* The Society are not to be considered responsible for the views of the 
authors of the papers referred to, nor for the manner in which those views 
may be eoapaned, the main object of this part of the Journal being to present a 
summary of the papers as actually published, so as to provide the Fellows with 
a guide to the additions made from time to time to the Library. Objections and 
corrections should therefore, for the most part, be addressed to the authors. 
(The Society are not intended to be denoted by the editorial ‘* we.”) 

t Rev. Sci. Nat., iii. (1884) pp. 362-462. 


5386 SUMMARY OF CURRENT RESEARCHES RELATING TO 


The spermatozoa, which are derived from these last, obtain their 
nutriment from the nucleus or the protoplasm of the male cell. 
When completely developed they are detached, become free, and are 
capable of acting as male elements. The nucleus undergoes dis- 
ageregation. } ; 

Between the early history of spermatogenesis and oogenesis there 
is a remarkable resemblance, but there is a difference on which the 
author specially insists; in the female element the multiplication of 
the ovular elements is generally limited to an early period, so that 
the female tubes of Pfluger contain a proportionately small number 
of ovules, each of which is of a considerable size, while, on the other 
hand, the male cells undergo a relatively more numerous series of 
segmentations, and the resulting elements are large in number and 
small in size. The view of many authors that the fundamental 
process of spermatogenesis is a simple succession of cell-divisions, 
ending in the formation of a cell small enough to be a spermatozoon is 
erroneous. . 

The essential conditions of oogenesis are the following :— 

A cellular element of the tissue of the ovary (not specially an 
epithelial cell) grows and acquires a more important layer of proto- 
plasm; the nucleus multiplies more or less by division; each of the 
nuclei acquires an atmosphere of protoplasm, and we thus have the 
female tubes of Pfliiger. The fundamental distinction only becomes 
apparent in the fourth stage, when the ovules, increasing in size, 
become differentiated by segregation and concentration, that is, by 
the formation of corpuscles, more or less hyaline, which make their 
way to the surface of the ovule. Here the essential difference com- 
mences, for in one case the centrifugal elements are developed and 
organized at the expense of the central element or nucleus, which is 
lost in the nourishment of the peripheral elements, in the other 
cases it is the centrifugal or peripheral element which is broken up 
or serves as food for the development of the central element, which 
then forms the egg. 

From these facts it is clear that the two elements of different 
Sexualities are the result of the elimination of one of them from a 
cellular body which at first possessed them both, and were, therefore, 
capable of a parthenogenetic mode of development. : 

The theory of sexuality put forward by Sabatier allows us, in his 
opinion, to understand how it is that one and the same sexual gland 
may, as in the ovotestis of hermaphrodite molluscs, give rise to both 
male and female elements, as well as such cases as those of Bufo, 
where one end of the organ is male and the other female ; the theory 
applies likewise to the occasional hermaphroditism in Vertebrates, 
which, most pronounced in Serranus, has been noticed by various 
observers in other Vertebrates, and even in man (Heppner). 

The sexual element is not always completely differentiated after a 
single elimination ; two or even more may be necessary, and this is 
especially the case with the female. The sexuality of the reproductive 
cell is due to the appearance of the precocious globules or “globules 
de début”; though a cell which has suffered such an elimination is 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 537 


truly an ovum, it is in many cases not completely so ; later eliminations 
are often needed to complete the work. 

The different kinds of globules given off from the egg-cell 
between the time when it is an asexual cell and a complete ovum are 
these :— 

1. Precocious globules which generally form follicular elements, 
and which give, so to speak, the first impulse to the cell towards 
a sexual condition. 

2. Globules which are more or less tardy in putting in an appearance, 
and which may be formed some time before or only just before 
maturity ; like the first, they arise by a simple differentiation in the 
protoplasm, and not by karyokinesis; they are the “ globules tardifs ” 
properly so called. 

3. There are globules which are cotemporaneous with the period 
of complete maturity, or the globules of perfect maturity. Most of 
these are due to phenomena of cell-division, and they are the polar 
globules properly so called. 

The author thinks that it is an error into which all embryologists 
have fallen to regard the cellular nature of the polar globule as a 
point of capital importance ; the principal, the necessary thing is the 
expulsion of a mass of protoplasmic substance which represents the 
male element ; it is only an accident that it is effected by a cellular 
mode of segmentation. The essential fact is, in other words, the 
completion of a sexual polarity. 

The lesson to be learnt from all the known facts may be thus 
summed up: Their common and very general character proves them to 
be of the highest value; they all point to an elimination, or a ten- 
dency to elimination, of a differentiated or undifferentiated portion 
of the central protoplasm, and they show that the concomitant 
phenomena are due to secondary circumstances which have no real 
importance on the significance of the globules or of the substances 
expelled by the egg. 

Considerable support, even if not categorical demonstration of the 
validity of Sabatier’s theory, is to be sought for in a comparative 
study of the method of oogenesis in animals which are both sexually 
and parthenogenetically reproductive ; if the theory is applicable to 
the facts, we ought to find in parthenogenetic eggs either a complete 
absence of, or a relatively small number of eliminated elements, the 
number and presence of which in sexual cells ought, on the other 
hand, to be distinct and pronounced. 

What observations (as yet few in number) the author has made on 
the history of the ova in Aphides seem to afford him the support he 
needs ; still stronger support is given by Weismann’s account of what 
obtains in the Daphnoidea, 

In his historical survey Sabatier refers, of course, to the well- 
known views of Balfour, and points out that that embryologist looked 
upon the portion of the germinal vesicle which the polar globule con- 
tained as being the essential point in the sexuality of the egg, and he 
urges that the phenomena of karyokinesis are of no real importance ; 

Ser, 2.—Vot. TV. PAY 


538 SUMMARY OF CURRENT RESEARCHES RELATING TO 


we must, however, note that the author speaks of “les obscurités et 
les indécisions des idées de Balfour,’ and cannot refrain from sug- 
gesting that it is possible that the English naturalist has suffered in 
translation. In many points, Balfour’s article, published in 1878, is 
in complete agreement with that now before us. 

Sabatier tells us that his essay is to be looked upon as offering a 
rational explanation, which may be acceptable for the present, and 
promises a future essay on the relations of heredity to the sexual 
polarization of the elements. 


Embryonic Germinal Layers and the Tissues.*— A. Kélliker 
states the conclusions of a valuable descriptive and critical essay in the 
following terms :— 

1. In all multicellular organisms all the elements and tissues arise 
directly from the fertilized egg-cell and the first embryonic nucleus ; 
and there is no such difference as is expressed by the terms archiblast 
and parablast. 

2. The tissues first differentiated have the characters of epithelial 
tissues, and form the ectoblasts and endoblasts. 

3. All the other tissues arise from these two cell-layers ; they are 
either directly derived from them, or arise by the intermediation of a 
median layer, which, when developed, takes an important part in 
forming the tissues. 

4, When the whole of the animal series is considered, each of the 
germinal layers is found to be, in certain creatures, capable of giving 
rise to at least three, and perhaps to all the tissues; the germinal 
layers cannot, therefore, be regarded as histologically primitive 
organs. 

5. In birds and mammals there is no primitive organ for the 
formation of connective substance, blood, or vessels. 

6. The elements of tissues already formed have, as it seems, the 
power of forming other tissues; those of the heterologous neoplasms 
are probably due to the remains of the embryonic cells or to elements 
similar in character to them. 

7. There is no justification for the classification of the tissues as 
archiblastic and parablastic, but, on the other hand, the old division 
of the tissues under four primary types, as suggested by the author and 
by Leydig, is still the most appropriate. 


Origin of the Mesoblast of Cartilaginous Fishes.t—C. K. 
Hoffmann commences his essay with the description of a develop- 
mental stage of Pristiurus metabolicus, which is a little later than 
Balfour’s stage B. In this there is as yet no trace of the notochord, 
and the mesoblast is only beginning to be formed. There is still a 
distinct medullary groove, and the intestine is in course of for- 
mation. 

The study of a number of sections, here described from before 
backwards, proves that the mesoderm forms a bilateral cellular layer, 
which grows forwards and backwards. Anteriorly it commences 


* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 179-213 (2 pls.). 
t Asch. Neerland. Sci. Exact. et Nat., xviii. (1883) pp. 241-58 (2 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 539 


with the bilateral evagination of the primitive intestine, so that it 
arises by delamination. This mode of development appears, however, 
to obtain only during the period in which the intestine is not yet 
formed. When the intestine becomes a closed tube, the mesoderm 
is formed directly at the expense of a mass of indifferent cells; in 
other words, the endoderm and the mesoderm are intimately united 
at the point where the embryo is growing forwards. The part of the 
mesoderm formed by a process of delamination is, comparatively, very 
small. At the edgesof the blastoderm and of the blastopore—the 
point where the embryo grows backwards—the three germinal layers 
are closely united. 

The notochord is formed by the endoderm, and, like the mesoderm, 
it grows forwards and backwards. Anteriorly the layers are so 
closely united that the cord there appears to be solid, and the anterior 
portion of the notochordal groove is, therefore, only feebly developed. 
Posteriorly the delamination is very pronounced, and the groove is 
wide and deep. The animal portion of the endoderm, or that which 
gives rise to the notochord, is separated, on either side, by a narrow 
but distinct cleft from the intestinal endoderm. Anteriorly the 
notochordal and intestinal endoderm are completely fused, and directly 
continuous with one another; posteriorly they are for a long time 
independent. This would seem to show that the mesoderm originally 
arose, at the hinder extremity, by a bilateral delamination of the 
primitive intestine, and this has, in the course of phylogenetic deve- 
lopment, been replaced by a process of folding. 

The author applies his knowledge of the development of the 
cartilaginous fishes to an explanation of the phenomena of the de- 
velopment of the notochord and mesoderm in birds; and comes, in 
conclusion, to the result that the phenomena observed in the mero- 
blastic ova of cartilaginous fishes amply demonstrate the truth that 
there is no well-marked division between mesoblast and mesenchyme, 
as has been insisted on by the brothers Hertwig. In these fishes 
only a small part of the median germinal layer is formed by the 
bilateral evagination of the primitive intestine—the mesoblast of 
the Hertwigs. The greater part of the layer would be, for the 
Hertwigs, mesenchyme. As a matter of fact, the two unite so early 
that it is impossible to say which had the earlier origin. The cells 
of the part which arise as mesenchyme have the same epithelial 
appearance as those which are formed by the evagination of the 
primitive intestine. The body-cavity—enterocele—which was at 
first found only in the part of the median layer which arose by 
delamination, soon extends into the region which, from its mode of 
origin, should be called mesenchymal. 


Intra-cellular Digestion in the Germinal Membrane of Verte- 
brates.*—J. Kollmann commences with an account of his observations 
on the cells of the endoblast in the lizard ; these cells vary consider- 
ably in size, and in their protoplasmic contents one finds spheres 
which are to all appearance of a fatty nature, and which are also 


* Recueil Zool. Suisse, i. (1884) pp. 259-90 (1 pl.). 
202 


540 SUMMARY OF CURRENT RESEARCHES RELATING TO 


present in large numbers in the fluid yolk; the nucleus of the endo- 
blast-cells is most remarkable for the changes which it undergoes in 
position. The author was most struck by the cells which appeared 
to open superiorly, and took them at first for artificial products; 
observation, however, led him to conclude that this was a definite 
physiological stage, and that being so he is compelled to suppose that 
the endoblast-cells do not merely maintain existence by diffusion, but 
also by direct massive wandering; there would appear to be not only 
a completely mechanical intaking, but as complete an outgiving of 
yolk-spheres. 

The author has also made some observations on the chick, and 
the result of his studies is his conviction that the cells of the 
endoblast take up food in an amceboid manner. He finds that ecto- 
blastic cells have a similar power of incorporating yolk-material, 
which they do by means of amceboid movement. In Lacerta agilis 
he has observed protoplasmic processes directed towards the vitel- 
line membrane, and has found in the interior of the cells small 
yolk-granules, and others which seemed to have been just incor- 
porated. 

In the acroblasts—as Kollmann terms the cells in the layer which 
lies between the ectoblast and endoblast—each of which is quite 
independent of the mesoblast, and in the cells derived therefrom 
which he calls “ poreuten,” a similar phenomenon has been observed. 
The latter are quite easy to find in the lizard, but are more difficult 
of detection in the chick, where they can only be seen after staining. 
In the lizard the author has been able to observe a direct movement 
of masses from the endoblast to the poreutes, a poreute sending out 
processes towards an endoblast-cell. 

The author concludes with referring the reader especially to the 
work of Metschnikoff, in connection with which he would wish his own 
fragmentary contribution to be studied. 


Larval Theory of the Origin of Cellular Tissue.*—A. Hyatt 
reviews the history of investigation among sponges ; concluding that, 
though true Metazoa, they possess characteristics which show them 
to be derived from Protozoa. The parallel between the development 
of the cell and egg in the tissue is strictly parallel with the evolution 
of nucleated from unnucleated forms in Protozoa. Recent investiga- 
tions have removed all objections to the homology of the egg or any 
cell with the adult of the nucleated protozoon; and the principal 
mode of reproduction by division is the same in all these forms. The 
egg builds up tissue by division after being fertilized by the male or 
spermatozoon, just as the spermatozoon builds up colonies after ferti- 
lization. 

Spontaneous division of a cell which undergoes encystment takes 
place and the spermatozoa which result from this are true larval 
monads. These resemble the monads derived from division of the 
encysted bodies of Protozoa in their forms and in their activity. 
They differ in being able to fertilize the female or ovum at once, 


* Science, iii. (1884) p. 337. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 541 


instead of being obliged to grow up to maturity before arriving at this 
stage. 

Thus all cells may be regarded as larval Protozoa, and eggs and 
spermatocysts as encysted larval forms, the spermatozoa being equi- 
valent also to larval forms which have inherited the tendencies of the 
mature forms in the Protozoa at the earliest stages. Thus the origin 
of the tissues in the Metazoa is in exact accord with the law of con- 
centration and acceleration in heredity. The cells are larval, which, 
in accordance with this law, have inherited the characteristics and 
tendencies of their adult ancestors in their earliest stages. The three 
layers can be accounted for as larval characteristics inherited from 
colonies of Infusoria flagellata, which had two forms (protective and 
feeding zoons), and then three (protective, feeding, and supporting), 
these corresponding to ectoderm, endoderm, and mesoderm. 


Development of Protovertebre.*—H. Fol, from a number of 
experiments on the order ef appearance of the protovertebre of the 
common fowl, comes to the conclusion that “ the first-formed somites 
of the body appear to be the most anterior of the whole series, and 
that they correspond, perhaps, to the cephalic region ; the long series 
of protovertebre are formed successively from before backwards.” 
Thus the vertebrate embryo commences, so to speak, as a head only, the 
rest of the body appearing by degrees. 


Experiments in Arrested Development.{—Another communication 
by M. Fol deals with some observations made by himself and §. 
Warynski which tend to confirm a previous discovery, that by 
momentarily heating the left side of an embryo chicken, a complete 
visceral inversion is obtained. The experiments consisted in pressing 
with the blade of a scalpel a portion of the embryo without injuring 
the vitelline membrane ; by so doing, the development of that portion 
lying outside the line of pressure was completely stopped. The de- 
velopment of the left side of the embryo was hindered by separating 
it from the afferent portion of the vascular area, and it appears to be 
by an arrest of development of the left side that a visceral inversion 
is produced, “ from which it may be concluded that this side ought to 
predominate to bring about the normal torsion.” 


Morphology of the Directive Corpuscles.t—O. Biitschli points 
out that, for a satisfactory comprehension of the morphological 
significance of the directive corpuscle, it is necessary to bear in mind 
the mode of sexual reproduction in the colonial Volvocinesr, a group 
of the Flagellata, which not only by their structure, but also by the 
characters of their method of reproduction, approach most closely to 
the Metazoa, even though their mode of nutrition is vegetable in 
character. The simplest case of sexual reproduction has been made 
known to us by the researches of Pringsheim on Pandorina. 

In it, at certain times, the cells of a colony give rise by successive 


* Arch, Sci. Phys. et Nat., xi: (1884) p. 104. 
+ Ibid., p. 105. 
~ Biol. Centralbl., iv. (1884) pp. 5-12. 


542 SUMMARY OF CURRENT RESEARCHES RELATING TO 


division to small sexual colonies, which arise in exactly the same way 
as the ordinary colonies which are merely formed by parthenogenetic 
reproduction. These small sexual colonies finally break up into the 
separate cell-individuals, which then copulate by pairs and form a 
resting zygote; a difference between the sexes of the separate 
individuals is not, or is only slightly, demonstrable. In the closely 
allied genera Hudorina and Volvox the facts are very different; in 
the former there appear at certain times colonies, which can be dis- 
tinguished as male and female, some produce nothing but ova, others 
as distinctly give rise, after repeated division, to spermatozoa, which 
copulate with and fertilize the female colonies. In Volvox it seems 
possible to homologize the male and female colonies, and indeed we 
cannot here correctly speak of colonies, but ought rather to regard 
what are so called as multicellular individuals of the simplest kind, 
and we have in it the best marked intermediate stage towards the 
sexual reproduction of the Metazoa. 

If we bear these facts in mind it is not difficult to suppose that 
the separation of a few small cells indicates the formation of a 
multicellular colony of “gametes” corresponding to the bundle of 
spermatozoa. 

As to the physiological significance of the directive corpuscle we 
have to decide between the views of the author that we have here to 
do with an elimination of certain nuclear constituents of the egg-cell, 
and that of Minot, that it is an elimination of the male element. 
Against the latter we have the fact that in the simpler cases of 
sexual reproduction in plants, as the alge, there is no process of 
elimination, such as is required by the hypothesis, and also the fact 
that it cannot be brought into accord with the known phenomena of 
parthenogenesis. 

In a note the author states that the recent observations of Fol, 
Sabatier and others, only came to his knowledge after his essay was 
completed, and he has not yet had the opportunity to bring them into 
accord with his own views. He takes occasion, however, to refer to 
some observations lately made by his assistant, Dr. Blochmann, who 
has discovered a very remarkable mode of cell-multiplication in the 
ovarian ova of ants; these have certainly nothing to do with the 
formation of the cells of the follicle, for the ovum was already 
surrounded by a chorion, before the numerous small nuclei, which 
appear in an altogether unexplained way, had become developed. The 
observations of Blochmann on ants are possibly to be brought into 
association with phenomena observed in the ova of Myriopods and 
Tunicates. 


Morphology of the Pineal Gland.*—F. Ahlborn has a short 
essay on the significance of the pineal gland, a subject which is of 
especial interest to English students on account of the recent hypo- 
thesis of Sir Richard Owen. The author comes to the conclusion that 
the pineal gland of vertebrates is to be regarded as the rudiment of 
an unpaired optic rudiment, and he bases this conclusion on the 


* Zeitechr. f. Wiss. Zool., xl. (1884) pp. 331-7 (1 fig.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 513 


similarity in the mode of its development and of the optic vesicle, 
that is, by a hollow outpushing of the central wall; on the origin and 
connection of the epiphysis with the optic region of the brain, and 
especially with the thalamus opticus; on the morphological resem- 
blance between the organ and the primitive optic vesicle; on its 
almost peripheral position in Petromyzontes, Selachii, and Ganoids, as 
well as its completely peripheral position (outside the skull and at 
the same level with the eyes) in the Amphibia; and, finally, on the 
primitive connection, detected by Van Wijhe, between the epiphysis 
and the neural ridge. 

The author, regarding the pineal gland as a frontal eye, thinks it 
justifiable to compare it with the unpaired eye of the Tunicata, and 
possibly also, of Amphiowus. 


Segmentation of the Vertebrate Body.*—F. Ahlborn, after a 
résumé of the theory of Gegenbaur as to the composition of the verte- 
brate skull, points out that an advance was made when later investi- 
gators discovered evidence in favour of the mesomeres of the head ; 
Gotte, who was the first in this line of inquiry, recognized four 
segments in the cephalic region. The author’s own observations on 
Petromyzon led him to the conclusion that the first two spinal 
nerves correspond to three mesomeres, and that the first neuromere 
nearly corresponds to the fourth and fifth mesomeres. From this it 
seems to follow that the first three myocommata were innervated not 
by a spinal but by a cerebral nerve; and that in the hinder part of the 
head of Petromyzon the parts of three true mesodermal segments are 
still retained. A further inquiry shows that the three first spinal 
nerves of Petromyzontes and of anurous Amphibia are completely 
homologous, and that the first cervical vertebra of the Amphibia 
corresponds to the fourth myocomma of the lampreys; if this 
result be correct it follows that the three first myomeres of the 
lampreys—which we have already recognized as typical cephalic 

ents—are homologous with the three hinder segments of the skull 
of the Anura. This remarkable agreement is further supported by 
the close systematic relation between these two groups which is 
spoken to by the large number of characteristics that they have in 
common. 

Gitte was followed by Balfour who attacked the problem by the 
road of the developmental history of the Elasmobranchii, and demon- 
strated the presence of a somatopleure and a splanchnopleure in the 
mesodermal elements of the head, as of the trunk; this considerable 
support to the doctrine of the metamerism of the head by the dis- 
covery of the head-cavities was succeeded by Marshall’s investiga- 
tions, which resulted in showing that metamerism first appeared in 
the ventral (or branchial) portion only, and by Van Wijhe’s work 
along the lines of the same theories. The studies of the last- 
mentioned anatomist lead to the conviction that the mesomerism, 
which is independent of the branchiomerism, as Marshall proved for 
the anterior, is true for the whole of the cephalic tract; it is a 


* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 309-80. 


544 SUMMARY OF CURRENT RESEARCHES RELATING TO 


typical segmentation which, primitively, completely agrees with the 
primary metamerism of the mesoblastic somites of the trunk. Of 
these cephalic somites there are nine. We may, in fine, conclude that 
the head of the Vertebrata ordinarily contains nine mesodermal 
segments, which, like the segmental musculature, might become of 
use to the specific cephalic organs ; but the earlier stages generally 
disappear and the metameres are no longer clearly seen to be separate 
segments. 

Ahlborn next addresses himself to the question of whether the 
gill-arches are homodynamous with the ribs, and comes to the con- 
clusion that the history of development clearly shows that the 
metamerism of the gill-arches, which according to Gegenbaur’s hypo- 
thesis is an expression of the primary mesomerism of the skull, is 
really nothing of the kind, but a segmentation which is caused by 
the primary branchiomerism of the enteron, and completely inde- 
pendent of the segmentation of the mesoderm. This conclusion is 
found to be confirmed by what obtains in Petromyzon and the Anura; 
the whole answer may be summed up in saying that the ribs are, but 
the gill-arches are not, segmental. 

The other problem proposed is: How far have the cerebral and 
spinal nerves a segmental nature, of the kind supposed by Gegen- 
baur? No primary segmentation affects the nervous system. Neuro- 
merism, therefore, is in the peripheral nervous system nothing 
more than a secondary repetition of all the pre-existing metameric 
phenomena in the body; it is segmental, when the nerves are dis- 
tributed to the segments of the body, but not in the branchiomerous 
organs. 

If the view be just that the nine rudimentary cephalic segments 
of the ancestor of the craniote Vertebrata were developed in just the 
same way as the trunk-segments, and if, at the same time, the medulla 
oblongata is a similar continuation of the spinal cord, we may con- 
clude that there were primitively nine pairs of spinal nerves in the 
hind-brain, of which the third, fourth, and sixth had only motor 
roots. But at the same time the so-called spinal-like cerebral nerves 
of the Craniota cannot, when we consider their morphological and 
physiological significance and the secondary character of neuro- 
merism, be any longer compared with the segmental pairs of spinal 
nerves. 


Embryology of Alytes obstetricans.*—M. Heron-Royer, gives a 
detailed account of the external modifications observed during the 
embryonic development of Alytes obstetricans. For the purposes of 
observation the eggs were placed on moist muslin between watch- 
glasses, and kept exposed to light and to a warm temperature. The 
egg has a large vitellus and a small cicatrix. Segmentation, which is 
limited in extent, commences after 12 or 13 hours with a dorsal 
streak with a broad, shallow blastopore. The vitellus is now spheri- 
cal, but soon becomes oblong with the formation of the elongated 
embryo. The embryo has paired ocular lobes anteriorly, and cor- 


* Bull. Soc. Zool. France, 1883, pp. 417-436 (1 pl.). 


~- 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 045 


responding branchial lobes posteriorly. In front of, and between, 
the anterior lobes is an air-bubble supposed to be respiratory in func- 
tion. By the 3rd day the four lobes have increased and coalesced to 
form a “racket-shaped figure.’ During the 4th and 5th days the 
cranium and sense organs (excepting the eye) are developed, the 
olfactory organs appearing much later than in other Anura. The 
branchie appear as digitiform processes of the lateral masses. By 
the 6th day they are six in number on the right side and seven on the 
left. By the 7th day there are ten for each side. In addition there 
are tentacular ramifications which coil about beneath the walls of the 
ovum. M. Heron-Royer compares these (provisional) organs with 
the arborescent vascular processes described by M. Bavay in the 
developing ovum of Hylodes Martinicencis, and justly explains 
their origin by reference to the terrestrial conditions of the deve- 
lopment of the young Alytes. 

The heart, first observed on the 6th day, is covered merely by a 
pericardium, and not by the vitelline sac, as in other Anura. On 
the 8th day appears the abdominal investment, inclosing a portion 
of the disappearing vitellus, and distinguished therefrom by pigmenta- 
tion. By the 9th day the yellow-coloured intestine is completely 
formed, and the vitellus absorbed. The eye is completed on the 
13th day, when the choroidal fissure disappears, and the iris, 
hitherto white, finally assumes its metallic yellow colour. 

On the 14th day the external branchie disappear, the right oper- 
culum being the last structure to be formed. The natatory mem- 
branes now develope, the caudal appendage elongates, and the embryo 
is ready to escape from the egg. 

There are three investments to the egg: (1) an “external en- 
velope,” inclosing an albuminous layer ; (2) an “inner capsule,” oval 
in shape; and (3) the “chorion,” directly investing the ovum proper, 
which is spherical. 

M. Heron-Royer disagrees entirely with the previous observations 
on the mode of the escape of the embryo from the egg. He finds 
that the young Alytes does not (as de L’Isle and others had asserted) 
simply split the envelopes of the ovum, like a bean-pod ; but rather 
that the exit of the embryo is at first conditioned by moisture. 
Exposed to moist conditions, the albuminous layer beneath the “ ex- 
ternal envelope” absorbs moisture and expands its investment. The 
“inner capsule” in the presence of the moisture becomes more supple 
and allows greater freedom of movement to the embryo, which now 
employs the external comb-like lamelle on its jaws to effect an open- 
ing, first in the chorion, then in the ‘inner capsule,’ and finally in 
the “ external envelope.” Finally, bending its body into a bow, and 
fixing its tail against the capsule, the embryo, by a final effort, forces 
its way from the egg “ comme un projectile.” Sometimes the young 
Alytes sticks half-way or endeavours to emerge tail first, usually with 
fatal consequences. 

M. Heron-Royer, by applying abnormal warmth and moisture, 
brought about the development of Alytes within 15 days. In normal 
circumstances, however, 24 days intervene between fecundation of 


546 SUMMARY OF CURRENT RESEARCHES RELATING TO 


the ovum and the escape of the embryo, the male Alytes retiring 
with the eggs wound round its legs to holes in the ground away 
from light and warmth. On warm nights in July (with the thermo- 
meter at 20°C.) the male Alytes carries his charges down to the 
water, and they then effect their escape, as above described. If the 
atmospheric conditions are unfavourable the Alytes, guided by “son 
instinct barométrique,” defers its passage from the land to the water. 


Development of the Nervous System of Forella,*—An account 
is given by V. Rohon of his observations on the development of 
the cerebro-spinal system in the trout. Briefly summed up, his 
results are that the first nerve-cells, distinctly recognizable as such, 
occur in this fish in the dorsal (sensory) tracts of the cerebro-spinal 
system. These “cells of Reissner” are multipolar, lie on either side 
in a longitudinal series (6 to 8 pairs in a myomere at the time of 
escape of the embryo from the ovum), and occur in the spinal cord 
earlier than in the brain. In the spinal cord they have relations to 
the dorsal roots of the nerves of the same, and of the opposite side. 
These cells occur in much the same fashion in the adult trout. 


Incubation of Eggs in Confined Air—Influence of Ventilation 
on Embryonic Development.;—C. Dareste describes the results of 
his experiments on the development of the embryos of fowls in a con- 
fined atmosphere. 

The eggs were placed in a 12-litre incubator, all the apertures of 
which were kept closed for 21 days. When opened several eggs 
were found hatched, but the greater number had perished, owing to 
the development in the albumen of microscopic organisms. The 
organism most often met with was a plant similar to yeast. 

In a second series of experiments the air was saturated with 
moisture, and in this case the albumen liquefied and leaked through 
the shell where it solidified in layers. This liquefaction appeared to 
be an obstacle to hatching ; nevertheless, the embryos from the sound 
eggs had here also reached their full period, whilst those from the 
infected eggs had perished, stifled by a species of Aspergillus that 
developed a mycelium in the interior of the albumen, then formed 
green fructifications in the air-chamber, and finally on the walls of 
the shell. 

The author concludes that air, modified by embryonic respira- 
tion, exercises no direct influence on the development and life of the 
embryo; but only an indirect one by facilitating the excessive deve- 
lopment of the parasitic organisms. Hence the necessity of renewing 
the air of incubators. In the struggle for life between the embryo 
and the parasites the advantage is in favour of the former, if the air 
be renewed and is sufficiently dry; whilst in air that is stale or 
saturated with moisture the advantage is in favour of the parasitic 
organisms. 


* SB. K. Akad. Wiss. Wien, 1884, pp. 39-56 (2 pls.). 
+ Comptes Rendus, xcvili. (1884) pp. 924-6. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 547 


B. INVERTEBRATA. 


Effect of High Pressure on the Vitality of Micro-organisms.* 
—A. Certes describes some experiments which he has made*on fresh- 
water and marine micro-organisms. 

At a pressure of 100 to 800 atmospheres, maintained for 7, 24, 
48, and 72 hours, some were killed; Chlamydococcus pluvialis were 
as lively as when they were put in the apparatus 7 hours previously ; 
Paramecium colpoda and Vorticelle (800 atmospheres for 48 hours) 
showed the “latent life” of Dr. Regnard.t The marine infusoria 
Euplotes charon, E. patella, and Pleuwronema marina retained the 
power of motion, while Holosticha flava and Actinophrys were 
dead. 

After 86 hours at a pressure of 520 atmospheres, the Chlamydo- 
cocci were mostly in the latent state, the completely green individuals 
having resisted the pressure better than those which were turning 
red. MRotifers were taken out in full activity, while Tardigrades 
revived after a time. 

In a case of bacteridian anthrax, blood submitted to a pressure 
of 600 for 24 hours maintained its full virulence. 


Micro-organisms of the Deep Sea.t—The researches of A. 
Certes on water and ooze from great depths tend to show that microbes 
that can live without air are absent from the bottom, while air- 
breathing forms are there present. The series of cultivation experi- 
ments which he carried on showed that the micro-organisms of deep- 
sea water were always much smaller and more active than those of 
the ooze. Ciliated or flagellate infusoria were absent. Successive 
cultivations resulted in the appearance of a number of large bacilli 
in active spore-formation. It has not yet been possible to decide 
whether the organisms found at great depths are identical with those 
already known. 

The researches of Regnard have shown that soluble ferments are 
not affected by pressure; under the influence of 1000 atmospheres 
starch was converted into sugar under the action of saliva. The 
other results obtained have been already noted.§ 


Origin and Formation of Glairine or Barégine.||—Supplement- 
ing a former paper on this subject, N. Joly describes the result of his 
observations on the origin and mode of formation of glairine or 
barégine in the sulphurous thermal waters of the Pyrenees. Micro- 
scopical examination, with a low power, of glairine and “ sulfuraire ” 
in the course of formation revealed the presence of a very consider- 
able number of animalcules, Nais, Cyclops, &c., in the full vigour of 


* Journ. de Microgr., viii. (1884) pp. 291-3. 

+ See this Journal, ante, p. 362. 

1 Naturforscher, xvii. (1884) pp. 193-4. 

§ See this Journal, ante, p. 362. 

|) Mem. Acad. Sci. Toulouse, y. (1883) pp. 118-25 (1 pl.). 


548 SUMMARY OF CURRENT RESEARCHES RELATING TO 


life, and this though the temperature of the water reaches 40° C. to 
49° ©. By their death and decomposition they furnish to the water 
the nitrogenous organic material which it holds in solution, and the 
gradual transformation of their remains into glairine precisely similar 
to that formerly observed is described by the author, who concludes 
that the concrete glairine of chemists is a complex substance, into the 
composition of which enters as a primordial element, a vast amount 
of animal and vegetable detritus. The “ sulfuraire ” is a very different 
production, but its fragments and those of various inorganic sub- 
stances go to swell the mass of the glairine. 

In a note to the paper is given a list of the organized bodies, to 
the number of 39, that have been recorded as occurring in sulphurous 
waters; whilst figures of Nais sulfurea and Cyclops Dumasti are 
given in the plate. 


Organisms in Hail-stones.*—Boyd Moss has, on two or three 
occasions during the last twelvemonth, collected a few hailstones in 
a conical glass, so that anything contained in them subsided to the 
bottom as they melted, and has always found organized remains, but 
he never had any idea of the quantity of these till a recent hail- 
storm. He figures the contents of a single hailstone (about 1/4 in. in 
diameter), which he placed, with every precaution as to cleanliness, 
between the glasses of a live-box. These consisted of diatoms, a 
living Ameba, a spore, probably of fungus, pale yellowish bodies like 
ova about 3 to 4 times the diameter of a human red blood-corpuscle 
(at least 40 of these), and a dark brown mass with small bright 
spherules. The Amceba and one diatom were in active movement. 
The spore (?) he calls the attention of microscopists to, and would be 
glad to hear if they are acquainted with it, “as it is one of several of 
the same kind which he discovered among the fibres of the heart of 
animals dead from cattle disease in India in 1870, and described in 
the ‘Monthly Microscopical Journal’ for December of that year, 
p. 312.” 


Mollusca. 


Suckers of Sepiola.;—M. Niemiec describes the structure of the 
suckers of Sepiola rondeletii. The general features appear to agree 
pretty closely with the account given by P. Girod of the suckers of 
other Cephalopods,{ but present some special peculiarities. 

The sucker consists of three parts: (1) the basal portion imbedded 
in the subepithelial tissues of the arm; (2) the peduncle; (8) the 
sucker proper. The basal portion is surrounded by a layer of annular 
muscles; within this is a longitudinal layer, while the centre is 
occupied by a series of radiately arranged fibres. These three layers 
are continued into the peduncle, and in the short arms terminate in 
the piston of the sucker, while in the two long arms they are inserted 
into a rounded cartilage. In other respects the suckers upon the 


* Knowledge, v. (1884) p. £23 (1 fig.). 
+ Arch. Sci. Phys. et Nat., xi. (1884) pp. 100-2. 
{ See this Journal, iii. (1883) p. 636. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 549 


short arms differ from those upon the long arms, the main difference 
being that, while the former are furnished with muscles directly 
continuous with those of the peduncle, the latter contain no muscles 
at all, but only a mass of parenchymatous tissue between the two 
epithelial layers. 


Histology of the Digestive System of Helix.*—From a study of 
H. pomatia var. grandis, Dr. F. Bonardi, who has made frequent use 
of double-staining methods, finds five distinct layers in the wall of 
the buccal mass, viz. (1) The outermost, of connective tissue, 
consisting of a fibrillated basis and of nuclei, and of a few distinct 
cells, which often contain calcareous concretions and refractive fatty 
globules ; and next to it (2) muscular, in two layers,-the outer longi- 
tudinal, the inner circular. They form an exception to the characters 
of the muscles in this animal, in often being in appearance trans- 
versely striated; this is, however, probably only owing to a pecu- 
liarity in the arrangement of the fibres within the sarcolemma. 
(3) Connective tissue, a continuation of the tunica connectiva of the 
other parts of the digestive system, containing granular cells. 
(4) Cylindrical epithelium, the cells very long; over the prominence 
described by Semper in the upper and lower parts of the buccal 
cavity it is ciliated. (5) Cuticula, of considerable thickness ; it is 
stratified in a longitudinal direction, and some large strie placed 
perpendicularly to the surface of the epithelium perhaps represent 
fine canals. The tongue consists chiefly of a muscular mass; this 
includes three distinct muscles, two of which are symmetrical and 
posteriorly separate, so as to embrace the lingual papilla; the third 
lies transversely below and unites them in the median and hinder 
parts of the tongue. All are isolated by connective tissue. The 
surface of the tongue is divided up by two sets of grooves into quad- 
rangular spaces, on which are placed a large number of whitish 
pyriform papille. The lingual papilla (at the base of the tongue) is 
covered by connective tissue, beneath which lies a layer of circular 
muscular fibres, covering a very distinct tunica connectiva, apparently 
not hitherto observed, containing oval cells with distinct outlines, 
imbedded in granular matter. It lies next to the cylindrical epithe- 
lium of the radula. 

The centre of the papilla consists of a transparent colourless 
substance, the external parts of which, near the radula, have the 
structure of connective tissue. The other parts contain fibrils going 
in various directions. At certain points they are inflated and have 
nuclei. They make up the “legs of the papilla,” and become mingled 
with the lateral muscles of the tongue. ‘The alimentary canal (viz. 
the cesophagus to the end of the duodenum) has (1) an external 
connective coat corresponding to the peritoneum of the higher ani- 
mals, underlaid by (2) double muscular, and (3) a connective layer 
corresponding to the vertebrate mucosa, and (4) an epithelial layer 
covered by a cuticula. The muscular fibres are not striated; those 
of the one layer are longitudinal, of the other transverse, some 


* Atti Accad. Sci. Torino, xix. (1883) pp. 33-46 (1 pl.). 


550 SUMMARY OF CURRENT RESEARCHES RELATING TO 


being oblique. The connective layer (3) has a lacunar structure. 
The lacune are lined by a cylindrical endothelium. The epithelium 
lining the depressions of the stomach, &c., may be said to be glandu- 
lar ; that occurring over certain conical processes of the connective 
layer is absorptive. From the distribution of the glandular and 
absorptive organs, Dr. Bonardi is led to abandon the terms cesophagus, 
stomach, and duodenum as expressing physiological facts. With 
the exception of the buccal portion, which is used for prehension, 
and the extreme posterior section, acting as an expelling organ, no 
separate functions are assignable to any part of the canal. The 
wall of the duct of the salivary glands consists of an outer cellular 
connective layer continued from the different glandules, of a median 
muscular coat comprising circular and oblique fibres, and of an 
epithelium made up of small cylindrical cells, on which no cilia were 
found. The refractive granules in the cells of the inner surface of 
the hepatic lobules are considered, with Barfurth, to be calcareous, 
but the ‘“ferment-cells” described by that author were not made 
out. Numerous muscular fibres were found in the peritoneum of 
the liver. 


Aplysie of the Gulf of Naples.*—F. Blochmann distinguishes 
three species of Aplysia in the Gulf of Naples by the following 
characters :— 


I. Lateral lobes free as far as the foot. A fine canal leads into 
the cavity which contains the shell. Behind the genital 
opening is a racemose gland. 

Animal 20-80 cm. long ; black, with white and grey spots. 
Aplysia limacina L. 

II. Lateral lobes fused together as far as the siphon. A wide hole 
without folded margins leads into the cavity which contains 
the shell. Behind the genital opening a group of unicellular 
glands, each of which has a separate external pore. 

a, Animal 10-20 em. long; clear reddish to blackish 
brown, white spots, the margins of which coalesce. 
The upper side of mantle has no cilia. Aplysia 
depilans L. 

b. Animal 7-15 cm. long; same colour as the last, the 
spots, however, smaller, and distinct, with usually a 
black border. Upper side of the mantle ciliated. 
Aplysia punctata Cuv. 


The paper contains further details of the anatomy of these three 
species, a complete list of synonyms, and a bibliography of the subject. 


Morphology of the Acephalous Mollusca.j—H. de Lacaze- | 
Duthiers devotes his first memoir on the ‘ Morphologie des Acéphales,’ 
to the remarkable Aspergillum (A. dichotomum) or Watering-pot Mol- 
luse, the animal of which is so rare, though the well-known shell is 


* MT. Zool. Stat. Neapel, v. (1884) pp. 28-49 (1 pl.). 
t Arch. Zool. Expér. et Gén., i. (1883) pp. 665-732 (5 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. | 


common enough. After an account of the difficulties which he per- 
sonally suffered in trying to get these molluscs for dissection, and a 
discussion of its general characters, the author describes the structure 
of the shell, in which he distinguishes the true from the false shell. 
The former, as is well known, consists of two small valves, and 
possibly also of zones which extend beyond their limits; the latter is 
tubular in form, and presents differences in sections taken at different 
points. In the terminal or lower part the calcareous tissue is pretty 
compact, and is formed of a number of layers which can be easily 
separated from one another, and do, as a fact, so easily part that it is 
impossible to make a satisfactory circular section of the tube. The 
facts of structure seem to show that the secretion of the false shell and 
its mode of growth depend on a deposit of crystalline particles, which, 
when effected slowly, gives rise to spheres, and when rapidly, to 
needle-shaped bodies. With regard to the marks or lines of attach- 
ment of the muscles, which are so prominent a feature in the shells of 
ordinary Lamellibranchs, it is here difficult to speak with certainty, 
and such lines of insertion as can be made out are hard to describe, 
inasmuch as they vary in depth in different individuals, and have not 
always exactly the same contour. 

To examine the animal that forms the shell it is necessary to break 
the latter, for it is impossible to extract by the lower orifice a conical 
body, in which the base has, of course, a longer diameter than its 
truncated apex. The body hasa chitinous envelope which is probably, 
though not quite certainly, secreted by the mantle; this last has no 
remarkable characteristics. The description of the mantle is followed 
by a general account of the structure of the animal, and the author 
then passes to the digestive tube. 

The dissection of the digestive tube was long and laborious on 
account of the intimate relations of the genital and hepatic glands ; 
as in other Lamellibranchs it describes a convoluted or appa- 
rently capricious course. The form of the anus is remarkable in 
consequence of its being affected by a constriction quite close to the 
end of the rectum; the extremity has the form of a small spherule, 
and the orifice is bilabiate. Within the interior of the intestine there 
is a projection comparable to the typhlosole of the earthworm ; in the 
stomach the same ingrowth has a number of folds. No cecum or 
hyaline style was to be observed. The cesophagus is certainly much 
longer in Aspergillum than in any other Lamellibranch; the mouth is 
very easy to find, and appears to have a definite relation to the superior 
orifice of the disk of the mantle. The liver, as in all its allies, is well 
developed ; though the condition of his specimens did not enable the 
author to make altogether satisfactory preparations, he thinks that it 
agrees in essential characters with that of other Lamellibranchs. 

The organ of Bojanus is heart-shaped in form and brownish in 
colour ; the pericardiac orifices are relatively easy to find, and, as in 
Anodon, the external orifices are situated at a high level. It is, 
without doubt, the organ that was described by Riippell as the 
liver. 

The central organs of circulation closely resemble those of other 


552 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Lamellibranchs, and the general plan of the vessels would seem to be 
on the same type. 

The gills are simple in structure and conform to the Lamellibranch 
type. The generative glands are united in the same individual ; the 
acini of the testis are large, smooth, or polyhedral, the ovary is also 
racemose in form, and is placed behind the male organ. After a de- 
scription of the nervous system and of the muscles, M. de Lacaze- 
Duthiers sums up the substance of his observations by pointing out 
that the animal of the watering pot shell is morphologically altogether 
like that of any other Lamellibranch. After an early period in 
which development goes on quite regularly, the body, owing to the 
excessive growth of its lower portion and the stationary condition 
of the upper, can no longer be withdrawn into its shell; then there 
commences a period of abnormal calcareous secretion, which gives rise 
to the peculiar form of the “shell.” But this remarkable phenomenon 
does not affect the essential characters of the animal, which is much 
more truly lamellibranch than Tridacna, Anomia, or the oyster. 

In conclusion, the author insists on the value of commencing the 
study of any given group by the consideration of the anatomy of a 
normal form. 


Molluscoida. 


Anatomy of Rhopalea.*—L. Roule describes the structure of this 
simple Ascidian, which is very abundant in the neighbourhood of Mar- 
seilles. The body is divided into two halves, of which the anterior is 
triangular and free, while the posterior is irregular in form and fixed ; 
the two halves are united by a delicate region of some length. The 
tunic, in its hinder portion, contains a number of vacuolated cells, 
which are absent from the anterior. By its general facies Rhopalea 
resembles the Clavelinide, but its structure and mode of development 
associates it with the Phalusiide ; and it may be considered as forming 
a link between the simple and compound Ascidians. In some points, 
such as the postbranchial position of the viscera, it approaches Ciona 
more than the true Phallusie, with which, on the other hand, it agrees 
by the possession of longitudinal folds in the wall of the branchia. 
Its affinities may be said to be numerous, and to form a bond of union 
between several diverse groups. 


Arthropoda. 
a. Insecta. 


Luciola italica.;— C. Emery, after some observations on the 
external characters of these insects, and the differences between the 
males and the females, in which he points out that in the male the 
whole of the lower of the penultimate (fifth) and last abdominal 
segments is phosphorescent, while in the female, which has seven 
abdominal segments, only two spots at the sides of the lower surface 
are luminous, passes to the structure of the luminous organs, in which 
there are the following, among other, interesting points. Prepara- 


* Comptes Rendus, xcviii. (1884) pp. 1294-6. 
+ Zeitschr. f. Wiss, Zool., xl. (1884) pp. 338-55 (1 pl.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. jae 


tions made with osmic acid showed that the smooth terminal branches 
of the trachex always end freely, and that they are never connected 
with other capillaries, either of their own or of other trunks; the 
author is so certain of this that he thinks that the anastomoses 
observed by Kélliker and others in the Lampyride can have no real 
existence. The structure of the dorsal layer of the luminous plates 
is very simple, no distinct cellular elements could be isolated, and 
the organs whether fresh, or after treatment with various reagents, 
showed nothing but opaque uric concretions floating in large numbers 
in the fluid. 

On comparing the luminous plates of Luciola with the light- 
giving organs of other Lampyride we are able to compare the clear 
cellular elements of the cylindrical lobules, which surround the vertical 
tracheal limbs and their branches, with the terminal tracheal cells 
described by M. Schultze. 

In Luciola the arrangement and distribution of the elements is 
much more regular than in other forms, and the plates appear to have 
attained to a much higher and more complete grade of development, 
as is expressed by the regular structure of the lobes, and by the 
special development of the tracheal end-cells, as well as by the constant 
dichotomous division of the termination of the trachee. 

The author discusses the homodynamy of the luminous organs with 
portions of the fat-body, and finds powerful evidence in support of it in 
the complete agreement in form, size, and relation to reagents exhibited 
by the nuclei of the luminous organs on the one hand, and of the 
fat-body on the other. With regard to the loss of substance by 
Luciole, Emery’s observations lead to the conclusion that a luminous 
and flying specimen loses daily about half a milligram in weight ; it 
is to be borne in mind that the imagines eat nothing. 

In conclusion, the physiology of the luminous activity is discussed. 
The males are either luminous for short and regular periods, or, when 
seized or injured, are without intermission, though not so remarkably, 
brilliant. In the latter case, which, it is clear, is the only one on 
which observations can be made, bright rings are seen on a dark back- 
ground, and it would appear that the luminous oxidation takes place 
at the surface of, but outside the substance of the parenchymatous 
cells. These appear to secrete the luminous material, which is taken 
up by the tracheal end-cells, and burnt by means of the oxygen in the 
fine branches of the trachew. This combustion can only take place 
when the chitinous membrane of the trachee is extraordinarily fine. 

The author does not think that this luminous power is a sexual 
means of exciting the rare females, but rather that it is a kind of warn- 
ing to insectivorous nocturnal animals ; the unpleasant smell which a 
Luciola gives off on injury makes it perhaps disagreeable to bats or 
other nocturnal animals. 


Development of Ccanthus niveus and its parasitic Teleas.*— 
H. Ayers finds that the ovum of Ccanthus—the tree-cricket—arises 


* Amer. Nat, xviii. (1884) pp. 537-40; from Proc, Boston Soc. Nat. Hist., 
1884, 56 pp. (8 pls.). 
Ser, 2.—Von, LV. 2P 


554 SUMMARY OF CURRENT RESEARCHES RELATING TO 


from a germarium, and not from an ovarian epithelium; and that the 
yolk is formed by cell-degeneration and not by secretion. The embryo 
exhibits a primitive segmentation, before the appearance of the 
permanent segments, each of the seventeen of which bears a pair of 
appendages, though some are rudimentary and deciduous. The dorsal 
vessel arises as a paired organ, the lateral halves of which give rise, by 
fusion, to a median tube, just as in some Vermes; the blood-corpuscles 
are the nucleoli of endodermic cells. A rather startling discovery is 
that of the gills, which Ayers describes as a pair of lateral outgrowths 
derived from the ectoderm of the pleural region of the first abdominal 
segment ; the gill-cavities are continuous with the body-cavity, and they 
appear to serve as channels through which the vascular fluid circulates. 
“The gill-pad is essentially a single-layered sac, with a much- 
constricted neck, evaginated from the pleural region of the abdomen ”; 
they are not tracheate gills, for they contain no nuclei. 

The author failed to observe any sharp distinction between a cell 
and its nucleus, or between a nucleus and a nucleolus; but he was 
able to detect the existence of segmental enlargements of the meso- 
dermic somites, similar to those from which the nephridia of worms 
take their origin. 

The author discusses the origin and function of the embryonic 
membranes (amnion and serosa), and points out that an answer is 
impossible if we do not clearly comprehend the relations of the 
embryo to its nutriment and food-yolk. They can hardly be supposed 
to have been primitively protective in function, and the egg is fur- 
nished with a protecting membrane (the chorion) before it leaves the 
body of its parent. Ayers comes to the conclusion that the serosa 
functions as a yolk-sac, while the amnion is the dorsal wall of the 
insect. It is to be noted that in Limulus the serosa does become a 
“vicarious chorion ” (Packard), and after the splitting of the true 
chorion, forms a protective membrane. 

The egg-parasite Teleas appears to be remarkable for the absence 
of embryonic membranes, and to give rise to a “ larval form intermediate 
between the blastosphere and the cyclops-larva of Ganin.” 


Origin of Bees’ Cells.*—Dr. Dénhoff urges objections to the 
views of Buffon, carried further by Miillenhoff, that bees’ cells are due 
to pressure, pointing out that there is no relation between the forms 
of the cells and of the bees’ bodies, and that he has observed a single 
female build a nest consisting of a number of six-sided cells; further, 
the difference seen in cells formed by bees and drones cannot be 
correlated with any differences to be found in the inhabitants; in 
the formation of the queens’ cells by other bees there is no pressure 
to produce the rhomboid pits; direct observation of the formation 
of a comb was not rewarded by any indications of pressure; no 
reasonable amount of pressure on the walls of cells seems to have any 
effect in altering their form. 

The author thinks that Darwin has erred in supposing that the cells 


* Arch. f, Anat. u. Physiol., 1884, Physiol. Abth., pp. 153-5. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 555 


have at first the forms which they have later on, whereas this is by no 
means the case; at first there are nothing but rhomb-shaped spaces, 
the size of which is gradually increased. 


Closed Poison-glands of Caterpillars.*—Dr. Dimmock states 
that if a Cecropia caterpillar “be examined carefully, the black 
spines upon its red, blue, and yellow knobs, or tubercles, will be seen 
to break easily from the tubercles, and a clear yellow fluid of dis- 
agreeable odour to ooze from each opening left by the injury. By 
crushing the tubercles with a pair of forceps the same strong odour 
is very noticeable, and by this mode of treatment one has no difficulty 
in proving that each tubercle, small or large, blue, yellow, or red, 
contains the odorous fluid. The red tubercles are seen, in sections 
cut with the microtome, to be divided into compartments, the cavities 
of each spine opening into a compartment at its basal end. The 
spines themselves are quite rigid and very brittle, so that they break 
away at a slight touch and leave a hole in the tubercle, out of which 
the odorous fluid pours, pushed by internal pressure. This fluid, 
which I have not examined carefully, but which I hope later to study 
chemically, is strongly acid to litmus paper, but causes a purple pre- 
cipitate in carmine solution.” The odour given out by these glands 
suggests at once their protective function. Similar glands, i.e. with 
no outlet until one is produced by external agency, are not rare in 
Bombycid larve. Karsten, in 1848, described the anatomy of the 
poison-glands at the base of the hairs of an American Saturnia. The 
secretion is ‘‘ perhaps formic acid or a formate in solution.” 


Gills of Insect Larve.t—G. Macloskie states that it is usual to 
describe the laminz of the pneumatic gills as containing systems of 
fine tracheal loops, somewhat after the pattern of a plurality of 
carbon-wicks in an Edison lamp. In a specimen, however, of the 
rectal branchiew of the larval Libellula, which he rolled under the 
cover-glass, he found that the multitude of tracheal ramifications 
ended cecally ; all were of about the same length, their extremities 
recurved within the containing sac, and their tips not all swollen, 
but rounded off. “As they are elastic, and the closing sac disten- 
sible, we { think it highly probable that with each water-inspiration 
the sacs enlarge and the tracheal spray (having air forced in by the 
forward compression of the large trachew) spreads out so as to bring 
the full tide of air close to the tide of water. Léon Dufour seems to 
have had some process like this in view, when he said that each 
lamella of the branchia of Potamophilus ‘is probably swollen during 
life by air transmitted by endosmosis. As we understand the case, 
the air is injected into the branchiw from the rest of the body by 
rhythmical contractions, and its gases then communicate endosmoti- 
cally with those in the tidal waters, so as to secure renovation.” The 
action of the trachew, Macloskie believes to be tidal rather than due to 
peripheral capillary circulation ; there being a flux and reflux, rather 
than a mere circulation of the air. 


* Psyche, 1882 (4). Amer. Natural., xviii. (1884) p. 535. 
+ Psyche, iv. (1883) pp. 110-2. t Amer. Natural., xviii. (1884) pp. 534-5. 
2P 2 


P 


556 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Dangers from the Excrement of Flies.*—B. Grassi describes 
experiments which show that flies are agents in the diffusion of 
infectious maladies, epidemics, and even parasitic diseases. 

On a plate on the table of his laboratory he placed a large number 
of the eggs of a human Nematode parasite (Trichocephalus). After a 
few hours he found, on some white sheets of paper hanging in the 
kitchen, the well-known spots produced by the excreta of the flies, and 
on a microscopical examination of these spots, several of the eggs of the 
parasite were found in them. Some flies coming into the kitchen were 
now caught, and their intestinal tract was found quite filled with an 
enormous mass of fecal matter, in which the presence of eggs of 
Trichocephali were detected. As it was practically impossible to keep 
all alimentary substances from contact with these flies, it follows that 
the chances of Dr. Grassi and his family being infected with Tricho- 
cephali were very great. As a matter of fact, the experiment was 
tried with non-segmented eggs of this worm. Another experiment 
was in the same direction. Dr. Grassi took the ripe segments of 
a Tenia solium (which had been in spirits of wine) and broke 
them up in water, so that a great number of the tapeworm’s eggs 
remained suspended in the fluid. The flies came to the mixture, 
attracted by the sugar, and in about half an hour the ova of the tape- 
worms were to be found in their intestines and in the spots. Had 
these eggs been in a recent and living state, they would doubtless 
have been just as easily transported. To those who care to try these 
experiments, it is suggested that lycopod powder mixed with sugar and 
water is a good material, as the lycopod spores are easily detected. 

It is self-evident that if the mouth-apparatus of the fly will admit 
of the introduction of such objects as have been above noted, that there 
will be no difficulty in its admitting scores of the spores of many 
parasitic fungi, and above all of those belonging to the Schisor: eee 
the possible cause of so much disease. Already Dr. Grassi has detected 
in fly excrement the spores of Oidiwm lactis, and the spores of ‘a, Botrytis, 
this latter taken from the bodies of silkworms dead of muscardine. 

There arises, of course, the question of how far the active 
digestion of the intestines of the flies may not destroy the vitality of 
germs or spores thus taken in, but it would seem probable that in 
many instances the larger bodies swallowed may not serve as objects 
for assimilation, but may be got rid of as foreign bodies, and it will 
be borne in mind that the flies themselves fall victims to the growth 
of a parasitic fungus (Empusa musce Cohn), which is probably taken 
first into their own stomachs. 


8. Myriopoda. 


Nerve- terminations on Antenne of Chilognatha.;—A pre- 
liminary note upon these structures is contributed by O. Biitschli; 
the results were worked out by Dr. B. Sacepine in conjunction with 
Dr. Biitschli, but having been left in an incomplete condition, a brief 
résumé of the more important new facts seemed desirable. 


* Arch. Ital. Biol., iv. (1883). See Nature, xxix. (1884) pp. 482-3. 
+ Biol. Centralbl., iv. (1884) pp. 113-6 (2 figs.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 557 


Previous observers have noted the occurrence of conspicuous 
structures upon the antenue of Chilognatha, which correspond to the 
so-called olfactory cylinders of insects recently studied in detail by 
Hauser,* and between the two there seems to be a general similarity. 

Each of the sensory processes is entered by a nerve which imme- 
diately divides into two branches, each covered with ganglionic cells 
which are distributed in two groups, the anterior one consisting of 
considerably smaller cells than the posterior ones; at the distal 
extremity the nerve-fibres again collect into a bundle and form the 
termination of the organ; that these fibres are differently constituted 
from those which enter the ganglion below is shown by the fact that 
their behaviour to staining reagents is different; the sensory process 
is often at the free extremity so that a direct communication is 
established between these nerve-endings and the outer world. 

A structure essentially similar to this is found in Vespa, but is 
differently construed by Hauser; according to him the posterior 
group of cells is not present since he only figures one nucleus, with 
several nucleoli however, while the anterior group of smaller cells has 
escaped his attention; accordingly the conclusion to which Hauser 
has arrived at is that the whole sensory structure is a single cell; 
whereas in reality it consists of a great number of cells. 


Ovum of Geophilij—E. G. Balbiani records some observations 
made on the development of the germinal vesicle and the follicular 
cells of the ovum in Geophilus. In the fresh ovum the germinal vesicle 
is spherical; when treated with dilute acetic acid a funnel-shaped 
hollow process is seen to arise from the germinal vesicle; one end of 
this is in close connection with the germinal spot and a process of the 
latter can be observed to penetrate the cavity of the funnel. It is 
covered externally by a delicate layer of vitelline protoplasm. In 
adult females this “nuclear appendix ” has the form of a long coiled 
thread, sometimes it is represented by a number of variously sized 
cylindrical masses, at other times by several round bodies scattered 
through the substance of the vitellus; the latter conditions are 
evidently the result of a division of the coiled thread-like nuclear 
appendix, but the division is never complete inasmuch as a considerable 
portion always remains adherent to the germinal vesicle. Each of 
these small round bodies into which the nuclear appendix splits up 
contains all the elements which go to form the ovum, viz. a portion of 
the germinal vesicle, the germinal spot, and the vitelline protoplasm. 
The wall of the follicle which incloses the ova is seen to contain a 
number of small cells which agree in every respect with these small 
cellular bodies resulting from the division of the nuclear appendix, 
and the view that they originate from the latter is confirmed by the 
recent investigations of MM. Fol, Roule, and Sabatier on the ovum of 
Ascidians. The follicular cells appear therefore to be the homologues 
of the spermatoblasts in the male, and the “ vitelline nucleus ” also 
corresponds to one of the same. 


* Zeitschy. f. Wiss. Zool., xxxiv. (1880) p. 367. 
+ Zool, Anzeig., vi. (1883) pp. 658-62 ch figs. ), 676-80 (3 figs.). 


558 SUMMARY OF CURRENT RESEARCHES RELATING TO 


y- Arachnida. 


Poison Apparatus and Poison of Scorpions.*—J. Joyeux-Laffuie, 
from his own studies and a consideration of what has been discovered 
by other naturalists, comes to the conclusion that the poison-organ 
of the scorpion (S. occitanus) is formed by the sixth or last somite of 
the post-abdomen, which terminates by a sharp process, at the ex- 
tremity and sides of which are two oval orifices by which the poison 
escapes. ‘There are two secreting glands, each of which opens by an 
excretory duct to the exterior. Each gland is situated in a cavity, 
which it completely fills, and which is formed by the chitinous 
skeleton and by an enveloping layer, formed by striated muscular 
fibres; it is by the contraction of this latter that the poison is forced 
out. The gland has a central cavity which acts as a kind of reservoir, 
and a proper wall, which is formed of a layer of cells that send out 
prolongations into the cavity, and of a layer of epithelial cells, which, 
in the fresh condition, have a finely granulated protoplasm; these are 
the secreting cells. The poison is very active, and, even in weak 
doses, soon kills most animals, and especially arthropods or verte- 
brates. The phenomena of poisoning are always the same, and take 
place in the following order—(a) pain at the point of injury; 
(6) period of excitement ; (c) period of paralysis. The convulsions 
which are characteristic of the second stage, are due to the action of 
the poison on the nervous centres, and especially on the brain; the 
paralytic phenomena are caused by the action of the poison on the 
peripheral extremities of the motor nerves, where they appear to _ 
have the same influence as curare. The muscles, the heart, and the 
' blood are in no way attacked, and the poison may therefore be cer- 
tainly placed among those which act on the nervous system. The 
scorpions found in France (S. ewropeus and S. occitanus) cannot cause 
the death of a human subject, and are only dangerous when several 
poison a man at the same time, or attack very young children. To judge 
by his bibliography, the author is unacquainted with the observations 
on the habits of scorpions, published in 1882 by Prof. Lankester. t 


Structure and Function of the Liver of Spiders.{— P. Bertkau 
finds that the so-called liver of spiders arises by the develop- 
ment of a considerable number of diverticula of different sizes from 
the widened portion of that region of the intestine which is found in 
the abdomen ; as these branch more and more they become united 
into a continuous whole by the formation of an intermediate tissue. 
Of the entire diverticula five are larger than the rest, and they are, 
like the intestine at their point of origin, glandular in nature. The 
epithelial cells are either small and oviform, closely packed with 
large colourless spheres, or they are larger and club-shaped, when 
part of their contents consists of small crystals and larger drops, 
which are yellow, brown, or green in colour. The chief function of 
the secretion of these glandular cells is the breaking up and altera- 


* Arch. Zool. Expér. et Gén., i. (1883) pp. 733-83 (1 pl.). 


+ See this Journal, ii. (1882) p. 612. 
} Arch. f. Mikr. Anat., xxiii, (1884) pp. 214-45 (1 pl.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 559 


tion of fibrin and other albuminous bodies. Spiders do not take in 
food in the solid form; they dissolve the muscles, &c., of their prey, 
and suck in the fluid food; this passes into the final branches of the 
enteric diverticula. 

The hind-gut commences just behind the last pair of these diver- 
ticula. The Malpighian vessels ramify in the intermediate tissue, 
and secrete guanin or an allied substance. This body may be found 
deposited in the outer layer of the intermediate tissue, and it takes a 
considerable share in the coloration and marking of the animal. 
On the whole, it would be well, in the present state of our knowledge, 
to substitute for the name “liver” that of “ chyle-stomach.” 

In the substance of the organ itself we may distinguish more or 
less regular hemispheres of various shades, an almost completely 
transparent tissue, and a system of fine richly branched Malpighian 
canals ; these last have fine canals which pass into wider collecting 
ducts, which open into a wide cloaca; the walls of this have a distinct 
muscular investment, formed by an outer layer of longitudinally 
and an inner of transversely disposed fibres. 

The author gives some account of the differences which the 
cxcal diverticula present in various genera of spiders and in forms 
allied to them. 


Anatomy of Acarina-*—J. MacLeod, in a preliminary notice, 
states that, in his investigation of the Acarina, he has made use of 
sections, after hardening in picrosulphuric acid or alcohol, and stain- 
ing with carmine, but that the successful results seem to have been 
greatly due to chance, specimens collected at the same time and 
treated in exactly the same way behaving very differently on treat- 
ment with hardening and staining reagents. The genera examined 
were Trombidium, Argas, Hydrachna, and Gamasus. 

He finds that the tracheiform excretory ducts of the salivary 
glands open separately into the labial groove at a short distance in 
front of the buccal orifice. The description given by Henking as to 
the presence of short narrow ducts arising from tubular glands is 
confirmed. The suctorial apparatus of Argas differs completely from 
that of Trombidium, accurately described by Henking ; it has three 
branches, each of which is bifurcated, and is provided with three 
radiating muscles. Notwithstanding the difference in their structure 
the two organs seem to obey the same dynamical laws. 

The author has been able to definitely assure himself of the com- 
munication between the stomach and the terminal intestine, which, 
denied by most authors, has only been regarded by Henking as pro- 
bable on 4 priori grounds. The communication is effected by a pair of 
lateral orifices, which are extremely narrow, and have their lips almost 
always closely applied to one another; the difficulty of detecting them 
is increased by the presence of a large number of almost villiform 
cells which are found around them. 

The terminal intestine is filled by a granular substance, which is 
composed of brownish-yellow granulations similar to those that are 


* Bull. Acad. R. Sci. Belg., lviii, (1884) pp. 253-9, : 


560 SUMMARY OF CURRENT RESEARCHES RELATING TO 


found in the stomach, and which are probably the true excreta; and 
of much larger granulations formed of concentric layers, which seem 
to be true calculi, which are formed not in the intestine, but in tubes 
which open into it, and in which similar calculi are to be found. 
These tubes appear to be Malpighian; but the chemical examination 
of the calculi is still to be effected. 

In conclusion, MacLeod throws great doubts on the exactness of 
the descriptions of the skeletal part of Acarina as given by previous 
writers, and promises to enter more fully into this subject. 


6. Crustacea. 


Sexual Colour-Variation in Crustacea.*—Differences in the 
colour of the two sexes among Crustacea are of very rare occurrence. 
Darwin in ‘ The Descent of Man,’ chap. ix., says he is acquainted with 
but two instances of this peculiarity: one in the case of Squilla 
stylifera, and a second in a species of Gelasmus, or fiddler crab. H. 
W. Conn records a third and very striking instance in Callinectes 
(Neptunus) hastata, the common edible crab of the southern coast of 
North America. There are a number of differences in the shape of 
the two sexes, but besides these they present a marked difference in 
colour. This colour-variation is confined to the first pair of thoracic 
appendages, the pair bearing the large chele. These appendages 
are of a yellowish brown on the upper surface, a whitish yellow on 
the outside, and of a brilliant blue on the inside and particularly at 
those parts which are protected from the light when the appendage is 
folded. It would seem therefore that this blue coloration was en- 
hanced by not being exposed to light. The colour of different 
individuals is tolerably constant and uniform. 

Between the colours of the male and female appendage considerable 
differences are discernible. The most noticeable difference is that 
the male appendage appears remarkably blue when compared with the 
female. This is due partly to the fact that the amount of blue surface 
in the male is much greater than in the female, and partly to the fact 
that the blue colour is of a much more brilliant hue. The blue 
colour in the male extends nearly to the tips of the two fingers of the 
chele, both the finger-like process of the propodite and the dacty- 
lopodite being largely coloured blue. The extreme tips are, however, 
of a brilliant purple. In the female these parts are of an orange hue, 
with not a trace of blue about them. Its tips are also coloured 
purple, but not so brilliant a purple as is found in the male. In the 
male the blue colour extends partly upon the outer surface. In the 
female it is confined to the inner surface and only extends to the base 
of the dactylopodite. The outer surface of the dactylopodite and of 
the finger-like process of the propodite are in the male white, while 
in the female they are reddish orange. Upon the male appendage 
there is no orange colour as a rule. 

These differences in colour are in all cases very marked, and will 
always serve to distinguish a male from a female appendage. No 


' Johns-Hopkins University Circulars, ili, (1883) p. 5. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 561 


colour differences are seen in any part of the crab except upon the 
first pair of appendages, and it is interesting to note that this sexual 
difference does not make its appearance till the crab reaches maturity. 
The chele of immature males and females cannot be distinguished 
from each other. Fritz Miiller says that the same is true of the 
Gelasmus species observed by him. On the other hand, considering 
the habits of Crustacea, these sexual differences can hardly be 
considered as the results of sexual selection. 


Observations on Tanais cerstedi.*—H. Blanc takes Tanais as his 
text for a study of the characters of the heteropodous Asellidz. Com- 
mencing with a general account of the body and its appendages, he 
states that the differences between the cephalothorax of the male and 
female are not so well marked in young examples, and are not at all 
apparent in embryos. In old specimens the chitinous integument is 
incrusted with calcareous salts, which have the form of small masses, 
crystalline in structure, which may be either needle-shaped or rounded. 
The concretions are altogether similar to those found by Hoek in the 
Caprellidz, and the differences in their form are due to the presence 
or absence of a hypodermic nucleus. The tegumentary glands 
are represented by three pairs of large glands which are placed 
beneath the lateral integument of the first three free segments of 
the thorax, and by twelve pairs of glands, which are much smaller 
than the others and are placed in the lateral portions of all the 
thoracic and abdominal segments, and in the head. The former 
are racemose in structure and closely resemble the same organs 
in Phronima, Hyperia, and Corophium. Each element of the racemose 
glands is formed of a mass of protoplasm, which contains two 
very clear nuclear vesicles, each of which is nucleolated. Each 
vesicle is, therefore, formed of two cells. The secretion from these 
cells passes out by small unbranched canaliculi, to reach the exterior by 
a single canal. The large thoracic glands are best developed in 
females carrying embryos in their incubatory pouches, and in them 
the glandular elements have their protoplasm almost entirely converted 
into a secretion. The product secreted hardens in the water and so 
forms a tube into which the Tanais may retreat ; when fresh, and to the 
naked eye, this secretion appears to be filamentous ; but when examined 
under the Microscope, it is seen to be composed of small rod-shaped 
corpuscles similar to those contained in the glandular elements. The 
secretion is more colloid than mucilaginous, for it does not coagulate 
with alcohol or form an emulsion with olive-oil. The secretion of the 
smaller pyriform glands probably has the function of secreting a 
product which prevents the animal from drying completely when it 
happens to float on the surface of the water. 

The supra-cesophageal mass is elongated in the male, and short, 
widened out laterally in the female. It is distinctly divided into a 
superior optic portion and an inferiorly placed part which is larger 
and forms the true cerebrum. The differences between the supra- 
cesophageal ganglia of the male and female are carefully pointed out. 


* Recueil Zool. Suisse, i. (1884) pp. 189-258 (3 pls.). 


562 SUMMARY OF CURRENT RESEARCHES RELATING TO — 


The arrangement of the nerve-cells in the ganglia of the ganglionic 
cord, as well as the double nature of the commissures which unite 
them, prove that the chain has arisen phylogenetically from two lateral 
nerve-cords. The whole nervous system of Tanais has a greater 
resemblance to that of the Isopoda than of the Amphipoda; the 
reasons for this statement are fully given. 

After many vain inquiries the author was at last able to observe 
in a young specimen the presence in the auditory vesicle of very fine 
and very short hairs, which were arranged in a single row on a small 
part of its inner surface ; no nerve could, however, be detected. Only 
twelve crystalline cones were found in the eye, and these were very 
short, and all of the same dimensions. 

The muscles of the body and the appendages were arranged in 
the manner usual among the Isopoda. The fatty body completely 
surrounds both the dorsal and ventral faces of the intestine ; below it 
also surrounds the ventral ganglionic chain and forms the so-called 
external neurilemma. In the abdomen, where it is most abundant, it 
forms two large masses on either side of the intestine. Itseems to be 
more abundant in young than in old animals; in old specimens it 
disappears altogether, so that it seems to play an important part in 
the nutrient functions of the animal, and in the development of the 
body and its organs. The adult males take no food. 

Respiration, in addition to being performed in the manner common 
among Decapods, is, as in Isopods, also abdominal. After a full 
description of the anatomy and physiology of the circulatory organs 
and of the digestive apparatus, in the course of which it is pointed out 
that the masticating stomach of the female is more complicated than 
that of the male, Blane passes to the renal organs; the seat of the 
urinary secretion is the fatty body, and the products of secretion are 
deposited more or less largely along the intestine; they are yellowish 
in colour and have the form of agglomerated masses of small rounded 
or angular corpuscles. Chemical investigations have demonstrated 
the uric nature of their deposits, and observation has shown that they 
are more abundant in old than in young examples. 

After some observations, not so complete as the author wished, on 
the sexual organs and on the “biology” of Tanais, Blanc discusses 
the question of whether they are Amphipods or Isopods; the balance 
of evidence seemed to him to be in favour of the latter, and to justify 
Milne-Edwards’ establishment of a group of ‘“‘ Asellotes hétéropodes.” 
As to whether Tanais is the ancestral form of the Isopods, as some 
have thought, it is necessary to be very careful, but, at the same time, 
one cannot fail to see such resemblances between Tanais and the 
zoéa-stage of Decapods as is represented by the mode of branchial 
respiration, the absence of abdominal appendages in the embryonic 
Tanais, and the possession of eyes placed on short stalks, and of an 
auditory vesicle which is open to the exterior. 


New and Rare French Crustacea.*—In his 33rd article under 
this title M. Hesse deals with several new parasitic Crustacea 


* Ann. Sci. Nat.—Zool., xv. (1883) art. No. 3, 48 pp. (3 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 563 


belonging to the order of the Siphonostomata, and especially to the 
Pelticephalidz, of the genera Nogagus, Lepimacrus (nov. gen.), 
Pandarus, and Cecrops ; all of these have been described and figured 
from living examples; they all live on fishes with an extremely thick 
skin, the scales of which are so closely arranged as to render 
penetration extremely difficult, and they all have a very special form 
of buccal apparatus, consisting of a rigid tube which is narrowed at 
its extremity, and which is deeply plunged into the flesh of the host 
so as to draw from it the fluids necessary for food. The fishes are 
all members of the group of the Squalide. 

After a full description of Nogagus spinacii (N. achantias), we have 
an account of an attached embryo; the latter was 3 mm. long by 1 
wide ; it was provided anteriorly with an umbilical process which 
served as an organ of attachment, but was so flexible as to be able to 
be turned in various directions ; on either side. of this were a pair of 
long flattened antennz formed of two joints, at the end of which were 
several divergent hairs. The eyes were relatively large and not 
widely separated from one another. The body was tubular in form 
and consisted of five rings, the first of which served as the point of 
attachment, ‘These embryos were very active and lively, and on several 
occasions were seen to be living, even when the Crustacea to which 
they were attached were far gone in the way of decomposition. 

The new genus Lepimacrus is founded on a single female specimen 
found on Lamna cornubica; the species is called L. jourdanii. 

Several species of Pandarus and one of Cecrops are next described ; 
and this is followed by some notes on their “ physiology ” and “ bio- 
logy.” It is pointed out that the mucilaginous tegumentary secretions 
of the piscine hosts render the skin more supple and more easily 
penetrable by the organs which attempt to perforate them. When 
deprived of this advantage and incompletely fixed to a thick and 
coriaceous envelope they easily fall off when the fish is captured and 
withdrawn from the water, and are then difficult to find.* The para- 

_ sites of the Squalide may be seen to select the thinnest parts of the 
skin, such as the axille or the eyes. Scyllium canicula, catulus, and 
annulatus have never been found to be infested with parasites, and it is 
a significant fact that their skin is very thick. 

Hesse is of opinion that Nogagus should be placed with the Pan- 
darine rather than the Caligine: and has some remarks on the term 
Siphonostomata, which has been rightly applied to those Crustacea, 
which, like the Pandarina, have a special syphonate buccal apparatus, 
by means of which they are able, after having pierced the skin of the 
fishes upon which they live, to penetrate their flesh and draw thence 
their nutriment ; this apparatus is not, however, found in Argulus, or 
Caligus, which are ordinarily associated with them, (It may be 
observed that one of the best authorities on the Copepoda—Professor 
Claus—makes a special division—that of the Branchiura—for Argulus.) 
The forms just mentioned bite rather than prick. For the Argulina 


* It may be pointed out, in this connection, that the number of parasitic 
Copepods collected by the ‘ Challenger’ was very small, 


564 SUMMARY OF CURRENT RESEARCHES RELATING TO 


and Caligina the author proposes the term of Rostrostomata —to which 
there is the obvious objection that it is a vow hybrida. ‘The author 
gives a table to show the systematic changes which he proposes. 


Vermes. 


Nervous System of Euniceide.*—G. Pruvot finds in Hyalinecia 
tubicola that the two central ganglia are so curved and connected 
by a thick median commissure that there is superiorly a “ ventricle ” 
which communicates by a large anterior cleft with thé general cavity. 
In the family generally we find that the cerebroid mass is made up of 
two distinct parts, one cerebral and one stomatogastric; the antennze 
and the organs of sense are innervated exclusively by the posterior 
or cerebroid portion of the mass; the unpaired posterior appendage 
represents a pair of appendages fused along the middle line. The 
stomatogastric centre alone provides the nerves of the palpi and the 
stomatogastric filaments, and the whole system presents essentially 
just the same arrangement as the general nervous system, for there 
is a supra-cesophageal centre, an cesophageal collar, and a ventral 
chain of, at least, two ganglia, the lower of which appears to the 
author to be constricted and to be formed by the fusion of what were 
primitively two ganglionic masses. 


Cerebrum of Eunice harassii, and its relations to the Hypo- 
dermis.}|—E. Jourdan describes the cerebral ganglia of Eunice harassit 
as being composed of a central mass of dotted substance, which is 
covered by a thick layer of nervous cells (the nuclear layer of 
Ehlers). Above this, and just below the cuticle, there are epithelial 
elements whieh are conical in form, and have their bases, instead of 
terminating on a membrane, prolonged into rigid filaments, which 
penetrate into the nuclear layer, and, by uniting, give rise to, as it 
were, pillars which pass from the cuticle to the mass of dotted 
substance. The protoplasm of these hypodermic cells is greatly 
reduced, and their nuclei are characteristically fusiform. They 
become lost in the nuclear layer, and closely fused with other fibrils, 
which have a similar histological character, but are of a different 
origin. 

The nuclear layer, which is rightly regarded as being nervous 
in nature, is made up of various elements. In section the layer forms 
a delicate plexus between the hypodermic pillars, and each of the 
spaces is occupied by a spherical nucleus. 'The nerve-cells of the 
layer are composed of a large nucleus, hardly any protoplasm, and 
a fine enveloping membrane; they give off one or two processes, 
which are exceedingly delicate when taken singly. 

The fibrils which are connected with them, but which, as has been 
already said, are of different origin, arise from the nerve-cells ; though 
their function is no doubt different to that of the hypodermic fibrils 
their histology is absolutely the same. The spaces left in the 


* Comptes Rendus, xcviii. (1884) pp. 1492-5. 
t Ibid., pp. 1292-4. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 565 


reticulum are filled by a fine protoplasm, which is perhaps comparable 
to the granular substance of the neuroglia of Vertebrates. 

The close relation between the hypodermic epithelial cells and 
their prolongations with their nerve cells and fibres, together with 
the absence of any histological differences between the two sets of 
fibrils, are especially interesting as calling to mind the characters of 
the nervous system of larval Annelids. 


Varieties of Branchiobdella varians.*—W. Voigt has a careful 
study on the variations of B. varians. 

He finds that we have here to do with an animal which may 
be of great importance in our knowledge of the mode of origin 
of species. He shows that it is on the very point of giving rise 
by its varieties to new species. The so-called B. parasita is 
undoubtedly the form from which the others have been derived. The 
fact that the variety hewodonta found on the gills of crayfishes in 
North Germany is replaced in South Germany by the variety astaci 
points to external influences as being the cause of this local dis- 
tribution ; the differences may be supposed to be due to temperature 
or to the qualities of the water, or the bodies dissolved therein. To 
such suppositions there are, however, powerful objections, and we 
must therefore look for the causes of variation in the animals them- 
selves. Differences have been observed in the size of the ova, and in 
the characters of the dissepiments between the segments which carry 
the segmental products; with these other differences appear to be 
correlated, but their exact relations have as yet to be carefully 
worked out. 


Ovum and its Fertilization (in Ascaris).{—The discrepancies in 
the recorded observations of fertilization in the ova of Echinoderms 
led E, van Beneden to study the subject in fresh types, and finally to 
pursue in the Ascaris megalocephala of the horse the important series 
of observations which he has recently published in great detail. 
The memoir is divided into four descriptive chapters and a general 
summary. 

The first chapter describes the constitution of the ovum and 
spermatozoon. 

The advantage to be obtained from studying the ovum in this 
Nematode is that in the uterus and oviduct definite stages of fertiliza- 
tion constantly occur at definite points. 

On quitting the ovarian rachis the previously bilateral ovum 
acquires an elliptic form, and—at the point of previous attachment 
—shows a micropyle, underlying which is a naked protoplasmic 
process, the plug of impregnation, situated on a polar disk forming a 
slight eminence on the transverse (or short) axis of the ellipsoid. 
Ultimately a delicate membrane comes to cover the ovum except at 
the micropyle. Within the so-called “nucleus,” or germinal vesicle 
(which is bounded by a membrane), is the “nucleolus,” or germinal 
corpuscle, consisting of two disks and situated peripherally on the 


* Arbeit. Zool. Inst. Wiirzburg, vii. (1884) pp. 41-94 (2 pls.). 
+ Arch, de Viol., iy. (1883) pp. 265-640 (1 pl.), 


566 SUMMARY OF CURRENT RESEARCHES RELATING TO 


prothyalosome, a differentiated, and slightly elevated, portion of the 
nuclear mass. 

Within the uterus of the fertilized female the zoosperms occur _ 
in four forms, marking four stages of development, though all are 
capable of fertilization. xcept in the first, or simply amceboid, 
stage, each zoosperm consists of a granular, nucleated, cephalic hemi- 
sphere, and of a caudal process containing a refringent body and fibrils 
of a contractile nature. A definite membrane surrounds the “ tail ” 
of the zoosperm, ending with a free border at the neck, and not 
investing the naked protoplasm of the cephalic hemisphere. 

The second chapter deals with the penetration of the zoosperm 
into the ovum,i.e. with “ the copulation of the sexual products.” On 
this subject Van Beneden has observed that, in Nematodes, as a 
general rule, only one zoosperm penetrates an ovum. The erroneous 
view that many zoosperms entered to fertilize a single ovum, is due to 
the presence of certain refringent bodies in the vitellus. (In Mam- 
mals, where many zoosperms commonly penetrate an ovum, one only 
effects fertilization, the others being assimilated as food.) The zoo- 
sperm always enters at the micropyle, round which the membrane of 
the ovum rises up to form a “perivitelline space.” On entering, the 
zoosperm applies itself to the “ plug of impregnation ” by its cephalic 
hemisphere,—its axis being thus applied in continuation of the 
embryonic axis of the ovum, and the homologous regions of the two 
elements being thus brought into contact. 

Aided by its own amceboid movements, the zoosperm is now borne 
into the ovum centripetally by the protoplasmic process to which it 
is applied. ‘The membrane of the zoosperm enters into intimate 
relations with the egg-membrane, finally fusing with it to form a 
continuous ovo-spermatic membrane. 

In his third chapter, Van Beneden deals with the “modifications 
which take place in the ovum from the time of copulation of the 
sexual products to the time when the unification of the mature ovum 
and zoosperm commences.” 

In Ascaris megalocephala a Upsiliform figure represents the first 
“ directive spindle” of Biitschli (Fol’s first “‘amphiaster de rebut”). 
This characteristic figure consists mainly of achromatic fibrils, with 
two chromatic disks, lying in a clear body (representing the prothya- 
losome) at the junction of the three limbs of the Upsilon. The 
chromatic elements are derived from the germinal corpuscle, the 
achromatic fibrils from the germinal vesicle and its membrane. 

As the zoosperm reaches the centre of the ovum, the vertical 
limb of the Upsilon becomes connected with it by filaments (probably 
muscular in function), and the figure becomes T-shaped, the trans- 
verse limb taking on the appearance of a spindle. Meantime the 
vitellus loses all traces of its radiate structure, becoming granular 
throughout. 

“The first polar body is now formed at the expense of the reduced 
prothyalosome and of the chromatic elements it contains. Hach of the 
two chromatic disks furnishes to the polar body the half of its sub- 
stance, and the prothyalosome divides tangentially. The elimination 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 567 


is not of a pole of the spindle, but takes place in the equatorial 
plane.” 

In the vitellus a homogeneous perivitelline layer is differentiated 
peripherally, and the refringent body in the caudal portion of the 
zoosperm is ejected into the perivitelline space. In spite of the 
striking analogies, the genesis of the first polar body is not to be 
compared to indirect cell-division. 

After the elimination of the first polar body there remains an 
homologous body, the deuthyalosome. This latter body increases in 
size at the expense of the vitellus and developes two “ asters” on its 
surface, one peripheral, the other central. Complicated pseudo-karyo- 
kinetic figures are now formed, but disappear before the elimination of 
the second polar body, which is formed from the deuthyalosome much 
in the same way as the first polar body from the prothyalosome, and 
apparently at the same spot on the ovum. A second perivitelline 
layer is now formed. The second polar body (i.) is the equivalent of 
the female pronucleus which remains behind, and (ii.) cannot be 
regarded as a cell. 

So far, Van Beneden concludes, no phenomena of true fertilization 
have occurred, merely “‘ phenomena of the maturation of the ovum.” 

The formation of the pronuclei and the true phenomena of fertili- 
zation are treated in the fourth chapter. The female pronucleus (the 
equivalent of the second polar body) consists of chromatic and 
achromatic elements, derived from the germinal corpuscle and the 
prothyalosome respectively. Contemporaneously with the expulsion 
of the second polar body, the male pronucleus is formed, exclusively 
from the nucleus of the zoosperm. Ultimately the two similar pro- 
nuclei meet in the centre of the reduced ovum (or female gonocyte, as 
it is now termed), and unite partially without fusion. A single 
dicentric karyokinetic figure is now formed (derived equally from the 
two pronuclei), and segmentation begins. 

“The egg, furnished with its two pronuclei, behaves like a single 
cell, and the sum of the two nuclear elements is equivalent to a 
simple nucleus. The first cell of the embryo is accordingly formed 
from the moment when the two pronuclei are fully developed ; fertili- 
zation coincides with the genesis of the two pronuclei.” 

Van Beneden concludes that “fertilization consists essentially in 
the formation of the female gonocyte, and its transformation into a 
cell, that is to say, in the replacement of the expelled elements by 
the new elements introduced by the zoosperm. The polar bodies are 
replaced by the male pronucleus.” 

All cells of the tissues are thus hermaphrodite, and fertilization 
is not a generation but merely a substitution requisite for the in- 
definite conservation of life. 


Spermatogenesis in Ascaris megalocephala.*—We have yet 
another contribution to our knowledge of the development of sperma- 
tozoa, from E. van Benedenand ©. Julin. The Nematodes in general 
and Ascaris megalocephala in particular lend themselves remark- 


* Bull. Acad. R. Sci. Belg., vii. (1884) pp, 312-42. 


568 SUMMARY OF CURRENT RESEARCHES RELATING TO 


ably to a study of the successive phases in the development of the 
spermatozoa, not only on account of the comparatively large size of the 
spermatozoa, but also because of the simple and typical arrangement 
of the male apparatus, which is formed by a single tube whose 
diameter insensibly increases in size from the blind end to the orifice. 
The best method of investigation is to use the double means of first 
examining successively dissected portions of the seminal tube, and of 
making a series of sections of a tube first hardened and properly 
stained. If we wish to avoid the errors into which preceding 
writers have fallen, we must be very careful to neglect no part of the 
tube. The later authors, such as Schneider, Nussbaum, and Hallez 
have, further, committed the fault of neglecting the bibliography of 
the question, and especially the excellent work of Munk published as 
long ago as 1858. 

The authors proceed to a description of the several parts of the 
male tube—testicle, efferent canal, seminal vesicle, and ejaculatory 
canal. They describe then in detail and sum up their results in the 
following terms : 

It is necessary, in the history of spermatogenesis, to carefully 
distinguish between the formation of the spermatogonia at the 
expense of the spermatomeres, and the division of spermatogonia into 
spermatocytes. The multiplication of spermatogonia appears to be 
effected, in A. megalocephala, directly and not by karyokinesis, 
while the spermatocytes arise by the indirect or karyokinetic division 
of the spermatogonia. The karyokinesis presents some special 
characters; the typical form of the chromatic cord is replaced by a 
rod-shaped form, and the primary loops have the shape of truncated 
cones. The longitudinal division of the primary loops results from 
the appearance of a circular vacuole in each of the pyramids; this 
vacuole extends to the equatorial plane, and brings about the division 
of the pyramid into two quadrilateral plates, which represent the 
secondary loops. ‘The polar corpuscles which occupy the centre of the 
attractive spheres are remarkable for their affinity for colouring matter. 
The asters may be distinctly seen to be the cause of the temporary 
division of the cell into three portions, separated by circular con- 
strictions. 

In the region where the spermatogonia are formed at the expense 
of the spermatomeres there are to be observed, between the cells, 
corpuscles which have a close resemblance to polar globules ; these the 
authors call residual globules. They appear to have been expelled 
by the spermatomeres after the karyokinetic metamorphosis, and the 
expulsion seems to be effected in the equatorial plane of the dicentric 
figure, as in the case of the polar globules. If this account be 
correct, the residual corpuscles are comparable to the polar globules 
of the egg. 

The spermatocyte, before becoming a spermatozoon, gives off a 
portion of its substance, which belongs to the cytophoral part; the 
formation of the cytophore is in no way comparable to a cell-division. 
Just as the egg, when completely matured, is a cell reduced to that 
which Van Beneden has called a female gonocyte, so is the spermatozoon 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ” 569 


a reduced cell. 'The reduction is accomplished in two distinct stages 
of development ; first affecting the spermatomeres, and then the sper- 
matogems. While each spermatocyte intervenes in the formation of 
a eytophor, the residual corpuscles are formed by the spermatomeres, 
in such a way that not only each spermatocyte (and, therefore, each 
spermatozoon), but also each spermatogon only possesses a reduced 
nucleus. 


Spermatogenesis in Ascaris megalocephala.*—P. Hallez, like 
E. van Beneden, has selected this convenient Nematode for the study 
of the phenomena of spermatogenesis. After a short description of 
the male organs, he points out that young of different ages as well as 
mature specimens must be examined. The spermatospores, which are 
formed at the blind end of the seminal tube, consist of a homogeneous 
extremely transparent protoplasm ; by division into four the nucleus 
gives rise to four protospermatoblasts, which form protospermatogems. 
The former give rise to a (second) generation of deutospermatogems, 
which are formed by a large number of deutospermatoblasts. The 
last become isolated, and consist of a homogeneous protoplasm and a 
nucleus which is deeply stained by reagents. As they increase in 
size their protoplasm becomes finely, then more distinctly granular, 
while the nucleus grows larger and developes a nucleolus. 

When they have reached a size of about 18 in diameter they 
divide by nuclear division; and this division is effected at about 
440 mm. from the blind end of the seminal tube. 

The deutospermatoblasts now become filled with refractive 
granules, and soon exhibit a phenomenon which has not yet been 
observed in the animal kingdom. They undergo conjugation by 
pairs, and the two become closely united with one another. The 
nuclei, after fusion, separate afresh. As they tend to separate from 
one another each gives rise to corpuscles, which resemble polar 
globules. 

The further development of the separated and ejaculated deuto- 
spermatoblasts must be made out in the organs of the female; when 
they first enter the ducts they are spherical cells, 18 or 19 w in 
diameter, their protoplasm is filled with refractive granules, and they 
have a nucleus which can be easily stained. After a certain time the 
refractive or nutrient granules disappear, and the deutospermato- 
blasts appear almost to be amceboid in character. They are now con- 
verted into spermatozoa, which are ordinarily conical or pyramidal in 
form; the nucleus is constantly found outside the spermatozoon, 
The fertilizing element is now ripe and may be seen to apply itself 
to and fecundate an ovum. 


Nematoids of Sheep’s Lungs.}—F. Karsch has a notice of A. Koch’s 
essay on the Nematodes of sheep’s lungs, in which especial attention 
has been given to Strongylus rufescens and its developmental history. 
The author found in the lungs of a Hungarian race of sheep a 
number of hair-like microscopic parasites which he regarded as new 

* Bull. Sci. Dép. Nord, vi. (1883) pp. 132-5. 
+ Biol, Centralbl., iv, (1884) pp. 51-3, 
Ser. 2—Vor, LY. 2 a 


570 SUMMARY OF CURRENT RESEARCHES RELATING TO 


and to which he applied the name of Pseudalius ovis-pulmonalis. The 
males are brown, the females milky white in colour; the latter lays 
its eggs in the finest branches of the bronchi, and the pulmonary 
alveoli; the young escape by the trachea, and the sexually mature 
forms enter by the same passage. The young make their way into 
mud or water, and thence pass first of all inio the stomach of the 
sheep; to return again to the gullet and so to get into the larynx. 
The author believes that he has here to do with a diminutive form of 
S. rufescens, which, by constantly living in the finest terminations of 
the bronchi, has accommodated itself to the diminishing calibre of 
these vessels. 


Free-living Nematodes.*—Up to the present the free-living 
Nematodes have received comparatively little attention ; absolutely 
nothing is known abont the exotic forms, and but few notices have 
been published of the forms that occur in Europe. In England 
Dr. Bastian has published an elaborate memoir of the free-swimming 
Nematodes, chiefiy the marine forms; while on the Continent Eberth, 
Schneider, Marion, and Biitschli have contributed largely to our 
knowledge of the group. The Monograph of De Man deals exclusively 
with those species that are found in the Netherlands. The work is 
divided into two parts, a general and a systematic ; in the first is treated 
the history of the group, their organization, mode of life, capture, 
methods of preparation, and their geographical and seasonal distribu- 


tion in the Netherlands. The second half contains a description of _ 


all the species found in the Netherlands, as well as a noiice of all 
the free-living species that have been described, with references to the 
published descriptions. The text concludes with two tables showing 
the distribution in the Netherlands of the different species, and a 
classification of the species according to the size of the body. The 
Monograph is illustrated by thirty-four plates. 


Trichina and Trichinosis.}|—This work is the result of a duty 
intrusted to J. Chatin by the French Government, who desired exact 
information as to the character of the preserved meats imported from 
America. The author concludes that“ in the name of public hygiene, 
as well as in that of agricultural interests, public opinion demands a 
careful examination of all animals that enter the country, whether 
they be alive or dead.” But he points out that it is for the legislator 
to prescribe the measures which are necessary for preserving the 
public health, and that the business of the naturalist is concluded 
when he has investigated the history and development of the parasite, 
and has drawn from these conclusions as to prophylactic methods. 
The work is one which should be known to all who are engaged in 
either the physical or legislative problems which surround the ques- 
tion of diseased meats. 


* «Die frei in der reinen Erde und im siissen Wasser lebenden Nemaioden der 
niederlandischen Fauna.’ Leiden, 1884, 34 pls. Cf. Biol. Centralbl. iv. (1884) 
pp. 191-2. 

7 ‘La Trichine et la Trichinose” Paris, 1883, 8vo, 257 pp. (15 pls). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 571 


Cystic Stages of Teniade.*—A. Villot finds, as a result of pro- 
longed inquiries into the characters of the cystic stages of Tape- 
worms that the mode of formation of the head is identical in all 
species, genera, and types. The true head, the future scolex, never 
proceeds directly from the candal vesicle ; it is always separated from 
it by an intermediate portion, which he has called the body, and 
which forms its immediate envelope. Tho differential characters 
which can be drawn from the modifications in structure and develop- 
ment have only a secondary value and cannot be used as the basis of 
a natural classification. In the next place, it is to be observed that, 
contrary to what is ordinarily taught, the caudal vesicle of the cysti- 
cerci may be formed in different ways; these differences have a future 
morphological importance. Cysticerci are either cysticerci properly 
so called, or are cysticercoids; the latter may be grouped under two 
heads and subdivided into six entirely new genera. The first section 
consists of those in which the caudal vesicle is formed by endogenous 
gemmation, and here we have Polycercus for the form found by 
Metschnikoff in Lumbricus terrestris, Monocercus for the so-called 
Cysticercus arionis ; in the second section, or that of those in which 
the caudal vesicle is formed by exogenous budding, we have Cercocystis 
for the form found in the larva of Tenebrio molitor, Staphylocystis for 
S. bilarius and S. micracanthus, Urocystis for a form found in Glomeris, 
and Cryptocystis for the curious form found by Metschnikoff in the 
visceral cavity of Trichodectes canis. 

The forms that are the most ancient and most closely approximated 
to the primitive type appear to be those that belong to the genera 
Urocystis and Cryptocystis ; it is in these that we observe the greatest 
independence between the different stages of development; the 
proscolex, cystic, and scolex-stages are perfectly distinct; the first, 
after having budded off the caudal vesicle separates from it, 80 soon 
as it has attained maturity, and no part of the proscolex is found in 
the perfect cysticercus. In Staphylocystis and Cercocystis the caudal 
vesicle adheres to the blastogen, but has only the function of a 
support or simple appendage. In the first section of the cysticer- 
coids the blastogen not only persists, but forms a permanent envelope. 
In passing from the cysticercoids to the true cysticerci we advance 
another stage in the scale of differentiation, and, at the same time, note 
a remarkable abbreviation in the history of development, for the stage 
represented by the budding of the caudal vesicle is entirely sup- 
pressed. This “serial co-ordination” of the cystic stages may be 
expressed by the simple law that the most differentiated types of 
organization have their development the most condensed ; those that are 
relatively lower are more diffused ; in other words, the complication of 
development and of organization are in inverse relation to one another, 


Anatomy and Development of Trematoda.{t—J. Bichringer devotes 
the greater part of this essay to sporocyst-stages, and has investi- 
gated the characters of Cercaria armata, C. macrocerca, CU. micrura, 


* Aun. Sci, Nat,—Zool., xv. (1883) art. No, 4, 61 pp. (1 pl.). 
t Arbeit. Zoul, Inet, Wiirzburg, vii. (1884) pp. 1-28 (1 pl.). 


202 


572 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Bucephalus polymorphus, Cercaria acerca n. sp. (found in various 
organs of Onchidiwm carpenteri), and another sporocyst from a species 
of Onchidium from Singapore. 

In describing the structure of the sporocysts, he deals with the 
epidermis, and points out that the so-called cuticle is not truly a cuticle, 
but is a membrane in which a varying number of nuclei are to be detected; 
its development is difficult to follow, but it would seem to be due to the 
fusion by peripheral growth of some of the outer cells of the gastrula, 
and to be comparable, therefore, to the ectoblast of the first order, 
which has been described by Schauinsland in the embryos of Trema- 
todes, and to the embryonic investment of Teenie, as described by E. 
van Beneden. On the whole, we are justified in regarding it as an 
epidermis and comparing it with the “ hypodermis” of other worms. 

The muscular layer is always very thin, and its outer layer consists 
of delicate, closely applied, circular fibres; below these is a longi- 
tudinal layer, which is often much less distinct. Cercaria macro- 
cerca is remarkable for having them broader and more distinct from 
one another than they are in other forms. 

The germinal epithelium is in most cases unilaminate, and varies 
in form in different species, the cells being cylindrical, cubical, or 
flattened. OC. macrocerca is here again remarkable for having large 
clear cells, which may be set in one or several layers, On their distal 
side there are nuclei, which lie in a protoplasmic fundamental substance, 
and which in section appears to form an anastomosing plexus. 

The so-called paletot is a fourth layer which is often present, and 
which, in the opinion of Leuckart, is due not to the guest but to the 
host; and the author is of opinion that the substratum from which it 
arises is the blood of the host, while the elements of which it is 
composed are the cells of the snail’s blood. After discussing this 
question at some length Biehringer passes on to the sucker or depres- 
sion which is often found at one pole of a sporocyst; its structure 
agrees so completely with that of the rest of the body-wall that it may 
be considered as a mere invagination of the whole sac. Jt no doubt 
serves as an organ of attachment. 

In dealing with the formation of the germinal bodies, and beginning 
by discussing the views of previous writers, and especially of Leuckart 
and A. P. Thomas, with the latter of whom he is in complete.agree- 
ment, he tells us that he is led by his own observations to think that 
the developmental cycle of the Trematoda is a real case of alternation 
of generation. 

Tn conclusion there are some remarks on the influence which the 
gradually developing brood exercises on the organization and activity 
of the sporocysts. When the brood remains at a lower grade of deve- 
lopment the nurse contrives to grow; later on, when the daughter 
generation is undergoing further development, it suffers a passive 
extension, but this does not equally affect the whole of the body of 
the nurse, but depends on the number and size of the germinal bodies 
which are to be found in any given zone of its body. At last, the 
whole mass forms a mere sac without any sign of organization, for 
the brood at last completely destroys the body of the mother. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 573 


Worm-fauna of Madeira.*—P. Langerhans has published the 
fourth of his contributions on the worm-fauna of Madeira, in the 
course of which he describes various new species and one new genus. 
Among other points of interest the author has some suggestions as 
to the divisions of the Serpulide, our knowledge of which is in a most 
unsatisfactory condition. In that family he recognizes three types; 
the first of these is Serpula itself, in which the thoracic segments 
bear only one kind of dorsal seta; here belong Serpula, Hupomatus, 
Pomatocerus, and Placostegus. Filograna is the second type, and in 
it all the thoracic segments behind the second have, in addition to 
the Serpulid sete, those of the kind first detected by Claparéde in 
Salmacina. Here we have Spirorbis and others. The third type is 
represented by Vermilia infundibulum, in which a fresh type of seta, ~ 
in addition to those already noted, is present. 

Of the twenty species of Nemerteans found by Langerhans, seven- 
teen are known to be members of the European seas. 


New Species of Rotifer.t—Sara G. Foulke describes a new species 
of rotifer under the name Apsilus bipera. In common with all 
members of the genus, they possess, instead of rotatory organs, a 
membranous cup or net, which is used for the capture of food. The 
specific distinction of the new form consists chiefly in the structure 
of the net, the presence of a true stomach in addition to the usual 
crop, and the presence of cilia inside the net. It is proposed to unite 
the forms Apsilus lentiformis Mecznichoff, Dictyophora vorax Leidy, 
and Cupelopagus bucinedax, Forbes, and the new species in one genus, 
Apsilus (Fam. Apsilide), in consequence of their strong points of 
resemblance. These are, briefly, the presence of two eye-spots, of a 
membranous cup, of a mastax exactly similar in all, of the absence 
of tail or foot-stalk, of the absence of carapace, and of the similar 
habits. 

Prof. Leidy subsequently declared all four forms to form the same 
species, with which opinion Miss Foulke does not agree. 


Echinodermata. 


Development of the Germinal Layers of Echinoderms.{—E. 
Selenka finds that egg-cleavage in Echinoderms is regular, but that 
of Ophiurids and Asterids is really “ pseudoregular,” and that of 
Echinids regular with polar differentiation ; we cannot as yet exactly 
define what we mean by a regular cleavage, and its various modifica- 
tions are as yet insufficiently known; we may, however, distinguish 
under its head those eggs into which the first two blastomeres are of 
the same size, and those in which cleavage is on the whole regular, 
with the exception of the first plane of cleavage. The various modes 
of cleavage exhibited by the eggs of Echinoderms are of no value for 
the phylogenetic history of the group; the influence of cenogeny is 


* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 247-85 (3 pls.). 

+ Proc. Acad. Nat. Sci. Philad., 1884, pp. 37-41 (1 pl.). 

t ‘Studien iiber Entwickelungsgeschichte,’ ii., Wiesbaden, 1883, pp. 28-61 
(6 pls.). 


574 SUMMARY OF CURRENT RESEARCHES RELATING TO 


apparent enough. The blastula is of the same thickness throughout ; 
in Echinids, and probably also in Asterids and Ophiurids the blasto- 
dermic cells are broader on the lower surface, in the Holothuroidea 
they are of the same size all round. The mesoblast arises from the 
primitive cells of the mesenchym and from the diverticula of the 
archenteron. The former, by means of their daughter-cells, and in 
the form of wandering cells, make their way into the blastoccelom and 
give rise to the circular musculature of the fore-gut and to the cutis. 
‘"he archenteric diverticula and their derivates consist first of a 
single layer of cells, from which later on scattered cells arise peri- 
pherally and form an outer ring of unicellular muscles. The 
explanation of this double mode of origin is not easy; it may be 
said that the two primitive cells of the mesenchym are the homologues 
of the two primitive cells of the mesoblast of molluscs, Arthropods, 
&ec., and that the archenteric diverticula are new formations (‘“ neo- 
morphs”) ; while there are several good reasons to be given in support 
of this hypothesis there are others that favour the view that the 
diverticula form the primitive seat of origin of the mesoblast and 
that the mesenchymatous cells are cenogenetic. Lastly, and this is 
perhaps the best view of all, the mesenchym-cells are portions of the 
archenteric diverticula, which in consequence of the modification of 
the larval life, have precociously separated from the rest. 

The “ blood-corpuscles ” of the water-vessels are found to arise from 
epithelial cells of the rudiments of the water-vessels, and those of the 
enterocelom from the peritoneal or ccelomic epithelium. - 

Evidence of the vermian origin of Echinoderms is afforded by the 
primary mesoderm having the form of two primitive cells, and by 
the bilateral symmetry of the larval organs. The division of the 
archenteric diverticulum into coelomic sac and water-vessels corre- 
sponds physiologically to that which the mesodermic sac undone Qos in 
Vertebrates, and to some extent in worms. 


New Genus of Echinoids.*—Prof. F. Jeffrey Bell institutes a new 
genus for the Hchinanthus twmidus described a few years since by 
Mr. Tenison-Woods, on the ground that the rows of ambulacral pores, 
instead of being approximated at their free end, tend to widen out in 
a lyre-shaped fashion ; and the genus is thereby removed “ from the 
direct line of ancestry through which the orthostichous passed to the 
petalostichous Echinids.” He alludes to the significance of this form 
being found in the Australian seas, and expresses a belief that further 
research will result in the discovery of other forms which have been 
unsuccessful in the struggle for existence. 


Revision of the Genus Oreaster.{—Prof. F. Jeffrey Bell revises 
the twenty-seven known species of Oreaster and describes five new 
species; in the systematic disposal of the species he has attempted to 
gain some assistance from the study of their post-larval development, 
especially as regards the number and arrangement of their spines ; he 


* Proc. Zool. Soc. Lond., 1884, pp. 40-4 (2 pls.). 
+ Tom. cit., pp. 57-87. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 575 


believes that “in the investigation of the spinulation of star-fishes 
there is a wide field for the study of those mechanical causes with 
which the zoologist is concerned.” 


Organization of Adult Comatulide.*—F. Perrier finds in Antedon 
rosaceus and A. phalangium that the “ axial organ ” is a tubular cavity 
with glandular walls; of its diverticula some appear in section to be 
cecal, while others are continued into canals, most of which pass 
towards the dorsal integument and form around the cesophagus the 
spongy organ of H. Carpenter. The canals (the author cannot call 
them vessels) take a sinuous course, anastomose frequently, and have 
walls which are clearly glandular; they open by ciliated infundibula. 
The author regards all these as parts of one and -the same system, 
and as comparable to the madreporic plate, sand-canal, and ovoid gland 
of Echinids, Asterids, and Ophiurids. Perrier finds in the characters 
of young larve—such as the disposition and mode of formation of the 
single canal—facts which lead him to think that the organization of 
the Comatulid is closely allied to that of other Echinoderms. Re- 
serving details he here points out that if we consider an urchin as a 
Crinoid whose arms have become firmly united with the disk (as is 
the case, for example, in Eucalyptocrinus), and whose mouth was 
situated at the point of insertion of the disk to the stalk, the nervous 
system and the ambulacral canals of the urchin would have exactly 
the same relations as those which are presented by the Comatulid. 
He further remarks that the calyx of numerous Crinoids becomes 
invaginated and presents points which are not without analogy to the 
lantern of Aristotle in certain (and especially in Clypeastrid) Kehinids. 


Ccelenterata. 


Anatomy of Campanularide.j—It is generally believed that 
the “theca” and the chitinous layer which covers the stem in the 
Hydroida is a secretion from the ectoderm layer of the polyp. This 
however docs not seem to be the case with the Campanularie. 
H. Klaatch has been furnished by a detailed study of Clytia johnston 
with evidence tending to show that the chitinous sheath of the 
Campanularie is a product of differentiation of the ectoderm, an 
epidermoid formation, the equivalent of a tissue. If this were not so, 
and if the chitinous layer were a mere secretion from the ectoderm, as 
it is in Cordylophora lacustris according to the researches of F. E. 
Schultze, we should expect to find the whole of the body of the polyp 
covered by a continuous layer of ectoderm entirely similar every- 
where, and the growth of the chitinous covering to be increased by 
the deposition of fresh layers of horny substance ; on the contrary, it 
appears that the outer epithelium which covers the tentacles, the 
head, and the “body” of the polyp is not continuous with that of 
the stem, but at the posterior end of the stomach bends back and 
becomes continuous with the calyx itself, actually passing into it, the 


* Comptes Rendus, xeviii. (1884) pp. 1448-90. 
+ Morph. Jahrb., ix. (1884) pp. 034-96 (3 pls.). 


576 SUMMARY OF CURRENT RESEARCHES RELATING TO 


process of the modification of the cells into horny matter having 
been clearly recognized; ‘‘in the stem no outer epithelium can be 
expected ; its absence is a proof that the chitinous sheath is a product 
of the differentiation of the ectoderm.” 

The chitinous theca therefore of Clytia is not homologous with 
that of Cordylophora. Beneath this “epidermis layer” of Clytia 
follows a deeper ectoderm layer, corresponding to the neuro-muscular 
layer of Hydra, &c., which differs in the “ body ” and stem of the polyp ; 
in the former there is a thick homogeneous layer to which the term 
middle zone (“ mittelzone”) is applied; this in the stem and the disk 
of the polyp becomes a distinctly cellular layer, one passing into the 
other without any break; the outer cellular layer of the stem is not 
therefore, as might appear from a casual inspection of Klaatch’s figure, 
the equivalent of the outer ectoderm layer—the “ epidermis-schicht,” 
but really represents the ‘“ mittelzone,” and has nothing to do with 
the formation of the outer chitinous layer which is formed by a meta- 
morphosis of the “ epidermis-schicht.” 

The different conditions of the middle zone may be perhaps 
explained by its different functions in the body and stem of the polyp 
respectively ; in the body it undergoes alterations of diameter in 
various stages of contraction, and from this fact appears to be rather 
muscular than nervous in nature; in the stem, on the other hand, the 
rigidity of the chitinous investment would seem to render the 
presence of a muscular layer unnecessary, and it is very possible that 
the cells which in this region of the polyp represent the “ muscular” 
layer of the body are modified to form nervous structures which 
receive impressions and control the movements of the muscular layer 
of the body, with which, as has been already stated, they are in direct 
connection. 


Structure of the Velellide.*—M. Bedot finds that in young 
Velellidz the two layers of which the crest of the pneumatocyst is 
formed are not united together; they first appear as a fold of the 
upper part of the pneumatocyst. The “liver” is of some complexity ; 
on its upper or convex part there is a single layer of cells which is in 
direct contact with the pneumatocyst; below this is a lamella, in 
which no cellular structure could be made out; against this there are 
applied the canals of the “ liver,’ which form a kind of roof fora 
large mass of cnidoblasts; the presence of these last demonstrates 
that the so-called liver does not perform hepatic functions. Below it 
there are again some canals which differ from the more superior by 
being unpigmented; they are attached to a similarly structureless 
lamella. ‘The two sets of canals are connected with one another 
through the substance of the organ. 

The complicated vascular system arises simply as two straight 
canals which open into the marginal one; they bifurcate at a short 
distance from their point of insertion. In the course of their develop- 
ment they become sinuous and give rise to a number of ramifying 
czeca, which anastomose with those of the adjacent canals. 


* Arch, Sci. Phys. et Nat., xi. (1884) pp. 328-30. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. wb 


Actinie of the Bay of Naples.*—A. Andres publishes the first half 
of his monograph, in which he limits himself to the bibliography and 
systematic descriptions of the species; this is very fully done, and 
the plates are of exquisite beauty. 


Protozoa. 


Morphology and Anatomy of Ciliated Infusoria.}—E. Maupas 
commences an important essay with a brief review of the more 
valuable works that have already appeared; after which he enters 
on a description of Colpoda cucullus, the food of which is stated 
to consist of bacteria, vibrios, micrococci, and small monads. Colpoda 
steinit is next dealt with, in which four forms are distinguished. 
These two species are very widely distributed. 

A new genus Cryptochilum is instituted for the Cyclidiwm nigricans 
of O. F. Miller, which, though closely allied to Paramecium, Col- 
poda, Colpidium, and Cyclidium, may, the author thinks, be justly 
distinguished from any one of them. A new species of this genus is 
C. elegans, which is much larger than C. nigricans ; it was discovered 
near Algiers. Paramecium griseolum of Perty is removed to this 
genus; and C. tortum, found near Algiers, and C. echini, which was 
found living parasitically in the intestine of Echinus lividus, are 
described as new species. 

Some parts of the structure of Colpidium colpoda are fully entered 
upon; Glaucoma pyriformis (e) is described in detail, and the 
structure of the mouth of G. scintillans is discussed. Ophryoglena 
magna is anew Algerian species which is fully described and com- 
pared with its allies. 

A new genus Ancistrum is instituted for the Opalina mytili of 
Quennerstedt, and for A. veneris galline, a new species found in 
Venus gallina at Algiers. ‘They lead the life of commensals, and the 
genus is allied to Pleuwronema and Ptychostomum. Quennerstedt failed 
to notice the mouth, which is, however, really present. 

Nassula oblonga (found in the sea off Roscott), Chilodon dubius which 
might almost be made the type of a new genus, Holophrya oblonga 
(sea off Algiers), and Lagynus crassicollis, from a similar locality, are 
all new species. Lowxophyllum duplostriatum (new species) is remark- 
able for the characters of its striation, which at once distinguishes it 
from all its allies. Interspersed with and following these descriptions 
are notes on some other species, after which the author enters upon a 
discussion of the organology of the Oxytrichida. Before defining his 
terminology he very justly urges that a good comparative morphology 
can only be established by the aid of a very exact terminology, based 
on as complete a comparison as possible. In the case of the Infusoria 
this may seem to be impossible, but it is because it has not been 
vigorously aimed at that such differences obtain in the comparative 
studies of even the best naturalists. To cite some of the terms em- 


* ‘Fauna und Flora des Golfes von Neapel. ix. Die Actinien,’ 1884, 459 pp. 
(13 pls.). 
t Arch, Zvol. Expér. et Gén., i. (1883) pp. 427-664 (6 pls.). 


578 SUMMARY OF CURRENT RESEARCHES RELATING TO 


ployed: the ventral surface always carries the mouth and the various 
appendages which function in locomotion and in the production of the 
nutrient currents ; the prebuccal and postbuccal regions vary greatly 
in their proportional extent, and it would seem that the suppleness 
and contractility of the body stand in an inverse relation to the 
development of the prebuccal region; this may be distinguished into 
a peristome and a lateral area; and they, also, differ in the pro- 
portional extent to which they are developed. Four kinds. of 
appendages may be distinguished: vibratile cilia; cirri, which are 
stylet-shaped, and much larger at their base than at their free-end, 
and which may be abdominal, transverse, or marginal; sete, which 
are filiform, homogeneous, and simple, but rigid like needles, and 
which may be dorsal or caudal; the latter are much longer and 
stronger ; lastly, the vibratile membranes are either those properly so 
called, or are buccal “ membranelles.” 

Actinotrocha saltans, Gonostomum pediculiforme, Holosticha lacazei 
n. sp. (seas near Algiers), H. multinucleata n. sp. (port of Algiers), 
Uroleptus roscovianus n. sp. are then described. 

The author proposes to replace the terms Protozoa and Metazoa 
by those of Cytozoa and Histozoa. 

Attention is directed to the characters of the naked Infusoria, 
which are not all members of the group Acinetz, but are found also 
among the Ciliata. The existence of forms without an integumentary 
layer shows that its presence or absence is in no way associated with 
the grade of development to which a Cytozoon may arrive, but that the 
protoplasm is ready to take on the most varied forms and structure, 
without the addition of an external protecting layer. The views of 
Hackel as to the typical constitution of the integument of an 
Infusorian are discussed, and the conclusion is come to that the 
‘cuticular layer” is perfectly distinct from the skeletal cuticular 
formation, that the ciliary and myophanous layers have no existence, 
and that the layer of trichocysts is a part of the sarcode and not of 
the integument. Contrary to the views of Hackel, with regard to 
whom Maupas expresses himself in the most energetic manner, the 
integument of ciliated Infusoria is looked upon as corresponding 
morphologically to the membrane of the cell, of which it has all the 
physical properties. The integument is, in fact, defined as any distinct 
superficial layer, which is intimately applied to the surface of the 
cell, and lives the same life as it does. The various conditions under 
which it presents itself are then described. 

The physiological properties of the sarcode or cytosome strike one 
by their resemblance to those of the body of the Rhizopoda, and lead 
one to think that an Infusorian may be defined very exactly as a 
Rhizopod inclosed in an integument and provided with appendages 
which are destined to fulfil the external functions which the sarcode 
of the Rhizopod performs for itself. 

The author’s observations on the trichocysts are stated by him to 
confirm those of Allman. The doubly refractive bodies which have 
been ordinarily regarded by those who have studied them as urinary 
concretions, offer us an important specific character, as they may be 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 579 


present in one species and absent from another which closely 
resembles it. The fibrillated appearance of some of the appendages is 
regarded as being due to the coalescence of separate cilia. When the 
integument is highly differentiated and very distinct from the 
underlying sarcode, the orifice of the contractile vacuole is re- 
presented by a permanent and constantly visible pore. The author 
concludes with some observations on the nucleus and nucleolus, in 
which he insists on the fact that the latter is certainly absent from 
some forms, even in those that are multinucleated, and he points out 
the difficulty which this absence presents to our accepting the views of 
Balbiani as to the mode of conjugation of the Ciliata. 


Trichomonas vaginalis.* —J. Kiinstler has now published the 
full text of his article on this flagellate, a preliminary notice of which 
was given ante, p. 67. 


Acanthometra hemicompressa.{—Dr. L. Car gives an account of 
this new Radiolarian which is characterized as follows :—The 
spicules are long and thin, pointed at the extremity ; the basal portion 
is quadrangular, the distal half is circular in transverse section, the 
proximal half lenticular, the two halves are of equal breadth, and 
this distinguishes the species from <A. compressa ; the spicules are 
elastic, but the elasticity is not so well marked as in A. elastica; the 
basal portion which is inserted into the central capsule is quadrangular 
and provided with triangular wing-like processes ; it terminates in a 
fine point; although these spicules are so elastic they appeared 
usually to be broken. The central capsule is transparent, and the 
distal portion only of the spicules projects outside; as in other 
Radiolarians the central capsule contains a number of colourless 
and yellow cells. In its general characters this species is inter- 
mediate between A. elastica and A. compressa. 


Orbulina universa.{—The life-history of this foraminifer has 
been a subject of much discussion. Pourtalés and Krohn both observed 
what was apparently a Globigerina in the interior of many Orbuline, 
and came to the conclusion that Orbulina was merely a stage in the 
life-history of Globigerina ; this opinion was combated by Carpenter, 
who adduced numerous reasons for retaining the two genera Orbulina 
and Globigerina as defined originally by D’Orbigny. 

C. Schlumberger, in numerous specimens of Orbulina universa 
dredged during the voyage of the ‘ Talisman’ from a depth of about 
2000 fathoms, observed the same phenomenon ; of the smaller examples 
some contained within their cavity a “succession of globular 
chambers, arranged in a spiral fashion, like those of certain Globi- 
gerine,” while others did not contain any trace of such a structure ; 
the very large specimens also were nearly always empty. 

On examining with care this Globigerina-like body its “ plasmos- 
tracum ” was found to be extremely fine, and traversed by widely 
scattered perforations ; the chambers forming the two first turns of 


* Journ. de Microgr., viii. (1884) pp. 317-31 (2 pls.). 
¢ Zoo). Anzeig., vil. (1884) pp. 94-5. 
} Comptes Rendus, xeviii. (1884) pp. 1002-42, 


580 SUMMARY OF CURRENT RESEARCHES RELATING TO 


the spiral are quite smooth, whereas the following ones are provided 
with spines which reach as far as the outer wall of the Orbulina and 
are there fixed firmly to it; the several chambers communicate with 
each other and also with the interior of the Orbulina. 

Now in an independent Globigerina the plasmostracum is always 
relatively thick, the perforations are close together, in short, it differs 
in many respects from this Globigerina-like body with which it only 
agrees in a general similarity of form. 

It appears, therefore, that the most probable explanation is that 
Orbulina is another instance of dimorphism among the Foraminifera 
such as has already been shown to exist in other genera of that order 
by the author and M. Munier-Chalmas. 


Nuclear Division in Actinospherium eichhornii.*—A. Gruber 
has a note on R. Hertwig’s observations on the division of the nucleus 
of this Protozoon. In the resting nucleus Hertwig distinguishes a 
nuclear membrane, which is best seen after the addition of reagents, 
the nuclear substance, and the framework of achromatic substance 
therein suspended. In the nucleolus there may be distinguished from 
the nuclein (chromatin) paranuclein which does not take up colouring 
matter and is much smaller in quantity ; the nucleolus varies greatly 
in form, and may become completely broken up into two or more 
nucleoli; there are often as many as six or even twenty, and they 
then form fine rods united into a rosette. 

When the nuclei begin to divide there appear two special proto- 
plasmic cones, which lie outside the nucleus, and which, though they 
give rise to a spindle-shaped body, are clearly not the so-called 
nuclear spindles. The nucleolus next begins to break up, and the 
nucleus forms a sphere filled with regularly distributed and very fine 
granules ; these pass to the periphery, where they give rise to two 
hyaline caps and an equatorial band of granules. In this last there 
appears a dark band, the nuclear plate, and in the rest of the granular 
mass fine filaments which give rise to the polar plates. These fila- 
ments traverse the nuclear plate and so form a system which extends 
directly from pole to pole. Lateral plates become formed which have 
the concave side directed towards the centre of the mass, and from 
these arise daughter-nuclei which form small, rounded, finely granular 
bodies. 

It is clear from these observations that the nuclein in the nucleus 
of Actinospherium is not a spongy framework ; the processes described 
are intermediate between the phenomena which obtain in other 
Protozoa on the one hand, and in animal and vegetable cells on the 
other. As in the former, the nucleus is sharply limited at every stage 
of division, and undergoes a biscuit-like constriction; the internal 
changes remind one rather of what obtains in wulticellular organisms. 
The remarkable polar plates find their homologues in the nuclei of 
the infusorian Spirochona gemmipara. Gruber ascribes the errors in 
his own previously published observations to the imperfect preserva- 
tion of the material with which he had to work. 


* Biol. Centralbl., iv. (1884) pp. 233-6. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 581 


BOTANY. 


A. GENERAL, including Embryology and Histology of the 
Phanerogamia. 


Homology of the Reproductive Organs in Phanerogams and 
Vascular Cryptogams.*—L. Celakovsky has made a fresh detailed 
investigation of this subject. He maintains his previous view, held 
also by Warming and Prantl, of the homology of the integuments of 
the ovule with the indusium of ferns, as is sufficiently proved by the 
phenomena of phyllody of the ovule, which show. that the ovule is 
due to a transformation of a segment of a fertile leaf together with 
the nucellus or macrosporangium belonging to it; the integuments 
being formed from it in just the same way as the indusium from the 
fertile leaf-tip of the Filicine. The nucellus is formed directly from 
the upper part of the ovular papilla; the integument then springing 
from its base and enveloping it; this being followed in most cases b 
a second envelope formed in the same way outside the first. The 
nucellus being homologous to a sporangium, the mode of formation 
of the ovule coincides with that of the sporiferous leaf-segment of 
Lygodium, the sporangium of Lygodiwm being formed at the apex of 
a segment of a fertile leaf, just like the nucellus on the ovular papilla, 
and the indusium round the sporangium just like the single or 
double integument round the nucellus. In Trichomanes the only 
difference is that the sporangium is replaced by the sporiferous 
receptacle. When normally dichlamydeous ovules undergo phyllody, 
they become monochlamydeous, and form a simple stalked cup which 
corresponds to the integuments, the stalk corresponding to the 
funiculus. The nucellus sometimes occupies its normal terminal 
position at the bottom of the cup, sometimes it is pushed towards its 
rim. The segment of a fern-leaf which bears the indusium on its 
under side corresponds to the outer ovular integument in Angio- 
sperms. 

In the Hymenophyllacez the indusium is not formed from the 
apex of the leaflet which corresponds to the nucellus or receptacle of 
the sorus, but as a lateral new formation, The single terminal 
sporangium appears to be more archaic than the polyangic sorus with 
its receptacle. The author believes that the sexually produced 
generation (non-sexual generation) of the first Vascular Cryptogams 
originated from the branching of the sporogonium of a moss. The 
sporangium of ferns is then homologous, from a phylogenetic point 
of view, to the sporangium of mosses, notwithstanding its different 
morphological value. The sporangium of Schizeacew is an older 
stage of development, and that of Ophioglossacez older still, where the 
integuments are entirely wanting, and the sporangium is therefore 
formed from the greater part of the leaflet, perfectly homologous to 
the naked ovule of the Santalacese, Balanophores, and Crinwm. 


* Pringsheim’s Jahrb. f. Wiss. Bot., xiv. (1884) pp. 291-378 (3 pls.). 


582 SUMMARY OF CURRENT RESEARCHES RELATING TO 


The original position of the nucellus on the leaf-segment is always 
terminal ; but as soon as the leaf-segment assumes a foliar character, 
it takes its place on its upper side; and this is a universal law for 
vascular cryptogams and phanerogams alike. 

If we now look at the homologies of the reproductive organs out- 
side the true Filices, we see that the fertile leaves of cryptogams with 
marginal sporocysts, like Botrychium and Ophioglossum, are the proto- 
type of the carpids of Phanerogams with marginal ovules; and that 
the fertile leaf of Lycopodiwm with axillary or subaxillary sporocyst, 
is the prototype of a carpid with axillary ovule, like Huphorbia and 
Ranunculus ; and that this is also the case with a carpid with ovule 
terminal to the axis of the flower, like Polygonum, which, notwith- 
standing this position, undoubtedly belongs to a carpid of the 
ovary. 

With regard to the phenomena of coalescence in the various 
groups, Celakovsky makes the following observations :— 

1. In Angiosperms the trumpet-shaped carpellary leaves of a flower 
coalesce into a septated ovary. 2. In Marsileacez the cornet-shaped 
leaf-segments of a fertile leaf coalesce into a 2- or multilocular sporo- 
carp, the homologue of an integumented ovule. 3. In Psilotee the 
sporangia coalesce with one another as the homologue of a branched 
but naked ovule. In Marattiacee the numerous emergence-like 
sporangia coalesce into a multilocular homologue of coalescent nucelli 
of an ovule. 

As regards the ovules of Gymnosperms, those of Cycadex are 
distinguished from the homologous sporangia of the Ophioglossacez 
only by being invested with an integument; and their carpellary 
leaves from the fertile leaves of Ophioglossaceze only by the latter 
being bifurcate. 

The Conifere are divided by Strasburger into two main groups: 
(1) the Araucariacee (including the Araucariew, Abietinez, Cupres- 
sinew, and Taxodiee), and (2) the Taxacee (including the Taxes, 
Podocarpew, and Cephalotaxez), which differ so greatly in their 
morphological characters that they must be considered separately. 

The ovules of the Araucariacez have only a single integument, 
and spring from the under side of the carpids which coalesce into a 
fertile scale and stand in the axil of a bract; turning towards it, 
according to the law of inversion, their upper side, and coalescing with 
it slightly in the Abietinez, very closely in the other families. The 
phenomena of prolification of the cone show that in the Abietines 
the simple scale-like carpels produce each one ovule on its under side. 
This is a carpel in its simplest possible form, and homologous to the 
possible case in which the fertile leaf of a cryptogam, e. g. Lycopo- 
diacez, should produce a single indusium on its under side. This is 
also the most probable interpretation of the structure in the Cupres- 

sinew and Taxodiee, though not so certainly as in the Abietinee. 
In Taxaceze the ovule has two integuments, except in Gingko 
(Salisburia) and Cephalotaxus, and is inserted on the upper side of the 
carpel, sometimes higher, sometimes at the base or in the axil of the 
leaf. The “cones” of the Cycadex, Podocarper, &c¢., are flowers 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 583 


composed of carpels, while those of the Araucariaces are true spikes, 
the bracts of which produce the coalescent carpels in their axils. 

The mode of formation of the anthers differs in Gymnosperms 
and Angiosperms. The type of stamen in the Coniferze and Gnetaces 
is derived from that in the Equisetacem, and more remotely from that 
in the Ophioglossacew ; the stamens of Cycadex corresponding to the 
more or less peltate type in ferns with sori on the under side, 
especially in Gleicheniaceew and Marattiacee. 

The anther of Angiosperms is developed from a sporophyll of the 
Ophioglossacee, but in a different way from that of Conifers, viz. 
from the form in Ophioglossum rather than in Botrychium or Helmin- 
thostachys. The difference between a pollen-sac of Conifers and a 
loculus of the anther of Angiosperms, is that the former is homo- 
logous to a single sporangium, the latter to a row of coalescent 
marginal sporangia. The normal anther of Angiosperms is also dis- 
tinguished by the peculiarity of having not two but four loculi, as is 
clearly shown by the phenomena of phyllody of the stamen. 


Influence of Light and Heat on the Germination of Seeds.*—A 
fresh series of experiments on this subject, undertaken by A. Cieslar, 
leads him to the conclusion that the effect of light on the germination 
of seeds is very complicated, and varies with the species, depending 
greatly on the amount of reserve food-material in the seed. The rays 
of different refrangibility also produce different effects. In white 
and yellow light much greater development takes place than in violet 
light or in the dark; and this difference increases with increase of 
temperature. He believes the effect to be greatly due to a trans- 
formation of light into heat. The production of substances which 
cause osmose in seedlings growing in white or yellow light is favour- 
able to germination, by bringing about increased root-pressure. 
Seeds with but a small amount of reserve food-material germinate 
better in light than in darkness; light promoting not only the 
peuetration of the roots into the soil, but also the copious production 
of roots. 

A. Ritter von Liebenberg{ confirms these conclusions on the 
whole, and regards the intermittent heat resulting from alternation of 
day and night as distinctly favourable to the germination of seeds. 


Origin of the Placentas in the Alsinew (Caryophyllez).{—Miss 
G. Lister, in view of the fact that in Lychnis the first developed ovules 
are developed along the unattached margins of the dissepiments in 
the upper unilocular portion of the capsule, the placentas being 
therefore carpellary, considers that as the capsule in Alsine is 
developed on essentially the same plan as that of Lychnis, we are 
bound to admit that the placentas in the Alsinex, from Sagina apetala, 
which most resembles Lychnis, to Cerastiwm triviale which most widely 
differs from it, are carpellary also. 


* Wollny’s Unters. aus d, Geb. der Agricultur-pbhysik, vi. (1883). See Bot. 
Centralbl., xviii. (1884) p. 15. 

+ Bot. Centralbl., xviii. (1884) pp. 21-6. 

t Journ. Linn. Soe, Lond.—Bot., xx. (1884) pp. 423-9 (4 pls.). 


. 


584 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Gemmez of Aulacomnion palustre.*—This moss was found in 
1882 growing in the propagating pits at Kew, where it flourished 
without, however, showing any trace of sexual organs. F. O. 
Bower finds that ordinary vegetative axes often bear towards their 
apices structures of a foliar nature, and show a special adaptation 
for effecting the asexual or vegetative reproduction of the plant. On 
passing upwards along one of these axes or pseudopodia, there is 
found a gradual transition from the normal leaf to the leaf-gemme, 
which are readily removed from the plant by a slight mechanical dis- 
turbance, and are then capable of immediate germination when laid 
on damp soil or floating in water. 


Relation between Increase and Segmentation of Cells.;—Prof. 
Beketoff criticizes Sachs’ theory as to the relations between the 
increase and segmentation of cells in the embryonal parts of plants. 
While he warns one against the application of geometrical theories to 
botany, he points out how some of the conclusions arrived at by 
Sachs could be more easily explained by the principles established by 
Hofmeister. 


Development of Starch-grains in the Laticiferous Cells of the 
Euphorbiacez.{—The development of the starch-grains in the latici- 
ferous cells of the Euphorbiacez is described by M. C. Potter as 
taking place in the interior of rod- or spindle-shaped starch-forming 
corpuscles which lie in the parietal protoplasm of the cell. 

The starch-grain is at first visible, through the agency of iodine, as 
a thin streak in the interior of the starch-forming corpuscle. This 
streak, through the deposition of starch, assumes a rod- or spindle- 
shape ; it increases in length and breadth, the starch-forming corpuscle 
at the same time increasing. When the starch-grain has attained nearly 
to its maximum dimensions in length and breadth, the starch-forming 
corpuscle collects at both ends of the rod-shaped grains, and there 
forms the masses of starch at the end of the rod, causing it to assume its 
remarkable shape, resembling a bone. The starch-grains are doubly 
refractive, but instead of the black or white cross of other starch- 
grains they show a central black (or white) line surrounded on both 
sides by white (or black) lines. 


Constitution of Chlorophyll.s— E. Schunck extracts leaves with 
boiling alcohol, and after some time filters ; the filtrate is mixed with 
its own volume of ether and two volumes of water; it then forms two 
layers, which are separated. The lower layer is yellow, and reduces 
Fehling’s solution. The upper layer is green, and contains all the 
chlorophyll; it is thoroughly washed free from everything soluble in 
water. When the ether is evaporated the bright green residue, 
dissolved in alcohol and treated with alcoholic potash, does not reduce 
Fehling’s solution, but if it is previously treated with concentrated 


* Journ. Linn. Soc. Lond.—Bot., xx. (1884) pp. 465-7 (4 figs.). 

+ Mém. Soc. Naturalistes St. Pétersbourg, xiii. See ‘ Nature,’ xxix. (1884) 
p. 461. 

{ Journ. Linn. Soc. Lond.—Bot., xx. (1884) pp. 446-50 (4 fies.), 

§ Proc. Roy. Soc., xxxvi. (1884) pp. 183-5, 285-6. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 585 


sulphuric acid in the cold, or if its alcoholic solution is boiled with 
hydrochloric or sulphuric acid, the alcohol driven off, the residue 
treated with water, filtered, and the filtrate made alkaline, mixed with 
Fehling’s solution and boiled, the usual glucose reaction is obtained. 
The glucose or glucose-like substance is a pale-yellow gummy 
compound. The author, therefore, concludes that chlorophyll is either 
a glucoside, or is associated with a glucoside. 

Cellulose accompanying the Formation of Crystals.*—A. Poli 
has already noted f the occurrence in the pith of a number of plants 
belonging to the order Malvacezx, of clusters of crystals attached to 
the cell-wall by strings of cellulose. He has now examined more 
closely the structure of these strings, and finds them to be hollow 
tubes. They generally exhibit swellings here and there, and bright 
refringent spots, which are probably the points of origin of new 
crystals. Their composition is the same as that of the cell-wall, and 
they not unfrequently become lignified in the same way. They 
appear to occur in all the arborescent species of the order, most beau- 
tifully in Malvaviscus mollis, but have not been observed in Malva 
sylvestris. 

Middle Lamella of the Cell-wall.{—In the course of his investi- 
gations on the continuity of protoplasm through the walls of cells, 
W. Gardiner has investigated the structure of the middle lamella of 
cell-walls, formerly known as “ intercellular substance.” He found 
the mucilaginous degeneration of the cell-wall to be a phenomenon 
of very frequent occurrence; and that this mucilage is very liable to 
be mistaken for protoplasm, owing to its being also stained by 
Hofmann’s blue. In certain cells, such as bast-prosenchyma cells of 
the pulvini of Mimosa, and the endosperm of many palms, the cell- 
walls consist of pure cellulose, and the middle lamella is but little deve- 
loped ; it is more resistant, but still distinctly soluble in sulphuric 
acid. In other instances, such as the lignified prosenchyma cells 
of the cortex of Lycopodium, it is well defined, but lignified, like the 
rest of the layers. In other cases it may be at once converted into 
mucilage. The great point with regard to middle lamellas other 
than cellulose is that in their substance the maximum amount of 
change appears to have taken place, i.e. almost the whole of the 
cellulose has been converted into lignin, cutin, or mucilage, as the 
case may be, and thus but little of the cellulose framework left, 
This will explain the fact that, after treatment with Schulze’s mixture 
or other oxidizing agent, the various cells readily separate from one 
another ; for the whole of the middle lamella has dissolved, the cellu- 
lose framework of the cells alone remaining. It would thus appear 
that in unaltered cellulose walls the middle lamella consists of dense 
cellulose, while in lignified, cuticularized, corky, or mucilaginous 
cells the changes which occur in the middle lamella are of the same 
character as those of the rest of the membrane, and have reached 
their maximum. 

* Nuoy. Giorn. Bot. Ital., xvi. (1884) pp. 54-6 (1 pl.). 
+ See this Journal, ii. (1882) p. 597. 
t Proc. Camb, Phil, Soe., v. (1884) pp. 1-20, 
Ser, 2.—Vou. IV. ZR 


586 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Intercellular Spaces between the Epidermal Cells of Petals.* 
—While the cells of the epidermis of leaves fit close to one another 
without any intervening spaces except the stomata, the case appears 
to be very different, according to G. H. Hiller, with the epidermis of 
petals, where there are very often spaces between the cells, especially 
in Dicotyledons. The size and form of these spaces vary with the 
species; in Linum usitatissimum they have a breadth of from 2°63 to 
7°175 p, and a length of from 13°15 to 15°78 yw. The largest 
measured had a diameter of 18. They are situated either between 
the walls of the cells themselves, and then usually at the point of 
contact of several cells, or in rib-like foldings of the cell-walls. On 
the inner side of the leaf they are usually open, where not acci- 
dentally covered by a parenchyma-cell, while on the outer side they 
are always covered by the cuticle. They almost always originate 
from ribs which must be regarded as foldings of the cell-wall, which 
ribs split at a certain stage of development. Very rarely they occur 
in epidermis with straight-walled cells, and then always from their 
effort to round themselves off. They are then always found at the 
point of contact of several cells. Intercellular spaces of this kind 
may be observed in the petals of Musa rosacea and Hrythrina crista- 
galli. 

Contents of Sieve-tubes.;—E. Zacharias has examined, by ordi- 
nary macrochemical tests, the contents of the sieve-tubes of Cucurbita 
Pepo, which flow out in large quantities when the stem is wounded, 
and can be readily separated from the cell-sap. They consist of 
albuminoids, non-albuminous organic substances, and inorganic salts. 

The albuminoid substances readily separate from the juice which 
flows from the sieve-tubes, after standing for a short time, in the form 
of a transparent, colourless, moderately stiff jelly. Chemical tests 
show that this substance is of the nature of fibrine, mixed with a small 
quantity of a substance insoluble in the gastric juice and in dilute 
potash ley. When this substance has been removed by concentrated 
alcohol, the filtrate turns the plane of polarization to the right. The 
substance which remains is of the nature of dextrin, which is trans- 
formed into glucose by dilute sulphuric acid. The presence of a 
nitrate or nitrite can also be determined both in the aqueous solution 
of the substance and in its ash. The question of the presence or 
absence of amido-acids and of organic nitrogenous compounds soluble 
in water in the contents of the sieve-tubes was not satisfactorily 
settled. 

Of inorganic salts there was found in the ash distinct evidence of 
the presence of magnesia. The probable presence in the sieve-tubes 
of potassium phosphate was also indicated, and to this is probably due 
the alkaline reaction of the juice. 


Organs of Secretion in the Hypericaceze.{—J. R. Green describes 
the organs that secrete the ethereal oil or resin with which the 


* Ber. Deutsch. Bot. Gesell., ii. (1884) pp. 21-3. 
+ Bot. Ztg., xlii. (1884) pp. 65-73. 
{ Journ. Linn. Soc. Lond.—Bot., xx. (1884) pp. 451-64 (2 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 587 


tissues of the Hypericacere abound. He concludes, (1) that the view 
advocated by Link, Martinet, and de Bary of the lysigenous origin 
of the reservoirs of ethereal oil in these plants is the correct one. 
(2) That there exists in many parts of the plants a series of ducts 
or passages differing only slightly from these reservoirs ; the differences 
being that they are not globular and isolated, but are generally 
connected more or less intimately with each other, and that their 
secretion is not a clear ethereal oil, but a viscid or resinous liquid, the 
points of agreement being those connected with their development and 
function. (3) In some species at least there is also a series of 
schizogenous ducts confined to certain portions of the phloém. (4) 
There are certain dark glands described in the paper which are in 
intimate relationship with the fibrovascular system. (5) The formation 
of resin and kindred secretions in these plants is confined to the parts 
where metabolism is active, and where there is a primary meristem. 
All such parts give evidence of such formation with the exception of 
the roots. 


Tracheids of Gymnosperms.*—M. Scheit describes the group of 
peculiarly thickened cells (the tracheid-seam of dé Bary) found in the 
leaves of conifers on both sides of the vascular bundle, at one time 
considered as a part of the transfusion tissue. In the living condi- 
tion these are filled with water or aqueous vapour, but not with air, 
as is shown by placing twigs of Pinus Pumilio in turpentine oil. 
The cells themselves are true tracheids, exhibiting sometimes a reti- 
culate thickening, sometimes bordered pits. These “seams” occur 
not only in conifers, but also in the other orders of Gymnosperms, 
the Gnetacez and Cycadex, where they consist of very small and few 
cells, greatly resembling the adjoining parenchymatous cells in the 
mode of thickening. They are therefore an anatomical characteristic 
of Gymnosperms generally. 

The variation in the mode of thickening in these cells corresponds 
to their function as a protection against the pressure of neighbour- 
ing turgid cells. Where the “seams” are separated from the 
parenchyma of the leaf by thickened sheaths, the tracheids have only 
bordered pits; when they are in immediate contact with the paren- 
chyma, they are thickened reticulately. The extent of development 
of these “seams” depends on the intensity of transpiration of the 
species. In Pinus Pinea, which spreads its crown as wide as pos- 
sible beneath the clear sky of Italy, they are very strongly developed ; 
while in Pinus Strobus, which prefers moist climates and thrives best 
in bogs, they are but very feebly developed. 


Apparatus in Leaves for Reflecting Light.t—O. Penzig has ex- 
amined the structure of the clusters of crystals found in the leaves of 
the Aurantiaces, clothed with cellulose, and attached to the wall of 
the mother-cell—the idioblasts of Pfitzer; and believes they are 


* Jenaische Zeitschr. f. Naturwiss., ix. (1883) (1 pl.). See Bot. Ztg., xlii. 
(1884) p. 74. 
+ Atti Soc. Nat. di Modena, i. (1883) (1 pl.). See But, Centralbl., xvii. (1884) 


p. 333. , 
2R2 


588 SUMMARY OF CURRENT RESEARCHES RELATING TO 


connected with the dispersion of the rays of light in the dense pali- 
sade-tissue. They always have their principal axis vertical to the 
surface of the leaf, and are fixed in this position by a peculiar band of 
cellulose. The rays of light fall, therefore, parallel to the principal 
axis of the crystals, and are dispersed on all sides from their reflect- 
ing surfaces, while those which pass through the crystals are refracted 
obliquely. It is possible that the subepidermal cystoliths in the 
leaves of Ficus have a similar property. 


Swellings in the Roots of Papilionacex.*—F. Schindler has 
reinvestigated this subject, with reference to the previous researches 
of other observers; and has come to the conclusion that the peculiar 
swellings are not due to the attacks of a parasitic fungus, but to 
hypertrophy of the tissue surrounding the vascular bundles, though 
in some cases there appears to be a phenomenon akin to symbiosis. 
The species in which the peculiar structures were observed, were 
Trifolium pratense, Vicia villosa, Phaseolus vulgaris, and Lupinus. 


Origin of Adventitious Roots in Dicotyledons.t—A. Lemaire 
discusses Van Tieghem’s statement that lateral roots have their origin 
in the peripheral layer of the central cylinder which he denominates 
the pericycle, and points out that all Van Tieghem’s examples are 
drawn from Monocotyledons. Lemaire finds among Dicotyledons two 
types, the first in which they spring from interfascicular spaces, the 
second from the pericycle, or layer of the central cylinder immediately 
beneath the endoderm. Im the latter case they are always produced 
in the neighbourhood of large primary bundles. The cellular portion 
of the pericycle of two plants examined (Mentha arvensis and Veronica 
Beccabunga) divides by tangential walls into two layers, the inner of 
which produces the central cylinder, the outer one again dividing into 
two layers. The lower of these gives rise to the cortex, while the 
peripheral layer developés, by successive divisions, into the cap and 
piliferous layer of the root. 


Crystals of Silex in the Vascular Bundles.{ — Pursuing the 
researches of G. Licopoli, R. F. Solla has examined the clusters of 
siliceous crystals found in the fibrovascular bundles of a number of 
species of palm, especially Chameerops humilis and Phenix dactylifera. 
He finds them in rows in the immature fruit of the first-named and 
in the trunk of the last-named species, in the latter case occurring 
also in the vascular sheath. They are found also in the scleren- 
chymatous cells in the endosperm of the seeds of Chamerops humilis, 
and in the spathe of Cocos Yatai. 'They vary greatly in size according to 
the species ; their chemical reactions show them to consist of pure silica. 


Effect of Heat on the Growth of Plants.s—Following out his 
researches on this subject, J. Wortmann gives the minimum, the 
optimum, and the maximum temperature for growth in various plants. 
As a general law, it may be stated that thermotropism is a phe- 


* Bot. Centralbl., xviii. (1884) pp. 84-9. Cf. this Journal, iii. (1880) p. 115. 
+ Bull. Soc. Bot. France, xxx. (1884) pp: 283-5. 

{ Nuov. Giorn. Bot. Ital., xvi. (1884) pp. 50-1. 

§ Biol. Centralbl., iv. (1884) pp. 65-71. Cf. this Journal, iii. (1883) p. 873. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 589 


nomenon of irritation altogether analogous to heliotropism, and that 
hence, in order to bring about thermotropic curvatures, the only factor 
to be regarded is the direction in which the rays of heat, if of sufficient 
intensity, strike the part of the plant in question. 


Curvature of Roots.*—J. Wiesner has made a further investiga- 
tion of the “darwinian” and the geotropic curvature of roots, with the 
following results :— 

1. The so-called “darwinian” curvature of roots, caused by injury 
to one side of the apex, has a double character, a secondary curvature 
taking place above the maximum zone of growth, while the primary 
curvature is below it. 

2. The primary curvature is the result of growth, the secondary 
curvature simply of turgidity, the cells above the injured spot in- 
creasing in length. If the root is decapitated, the zone above the 
wound, within which the darwinian curvature takes place, is elongated, 
the cell-walls becoming more extensible. 

8. The darwinian curvature combines with other paratonic 
nutations, as for example with geotropic curvature. Geotropism 
frequently neutralizes the darwinian curvature. 

4. The entire growth of decapitated roots grown in damp media 
is less than that of those that remain uninjured; while the lower zone 
of such roots nearest the apex undergoes great extension in consequence 
of the increase of extensibility of the cell-walls. In decapitated roots 
grown under water this pathological increase in length is so great 
that the total growth of such roots is greater than of unmutilated ones. 

5. The decapitation of roots causes a diminution of the turgidity 
of the cells; and since geotropic curvature decreases with this 
diminution, it follows that decapitated are less geotropic than uninjured 
roots. ; 


Torsion as a Cause of the Diurnal Position of Foliar Organs.;— 
According to O. Schmidt, light, by promoting the growth in length of 
the shaded side of organs, can produce curvatures, but not torsions. 
So-called heliotropic torsions are due to the action of gravitation. 
The ordinary diurnal position of leaves is a result of the combined 
action of light and of gravity, the latter causing the torsion without 
which the position could not be attained. 


Assimilative Power of Leaves.t—J. Sachs has carried out a series 
of experiments on a number of plants growing in the open ground, 
for the purpose of ascertaining the phenomena connected with the 
formation of starch in the chlorophyll-grains, and its disappearance 
under normal conditions of vegetation. The results arrived at are 
very remarkable, in showing the extraordinary rapidity with which 
starch is formed and again disappears when the conditions of vegeta- 
tion are favourable. The plan pursued was to remove the chlorophyll 
by alcohol, and then employ the iodine test to determine the presence 
of starch. Leaves may be perfectly decolorized by first boiling in 


* Anzeig. K. Akad, Wiss. Wien, 1884. See Bot. Centralbl., xviii, (1884) p. 95. 
+ Ber. Deutsch. Bot. Gesell., i. (1883) pp. 504-11. 
t Arbeit. Bot. Inst. Wiirzburg, iii, (1884) pp. 1-33. 


590 SUMMARY OF CURRENT RESEARCHES RELATING TO 


water for a few minutes, and then for a short time in alcohol. If 
then placed in a strong alcoholic solution of iodine, the decolorized 
leaf will be stained a buff-yellow if no starch is present, blue-black if 
starch is present in great quantities, with intermediate shades according 
to the amount of starch. 

The formation of starch is entirely dependent on the presence of 
light; and Sachs’s experiments show that the starch formed during 
the day may disappear completely during the night; the cells of the 
leaves being full of starch in the evening and quite empty in the 
morning, when the conditions of temperature are favourable. It is 
stated that the starch disappears in the form of soluble glucoses, 
which travel, through the vascular bundles, to the parts where they 
are wanted for purposes of growth. Although this process takes place 
chiefly in the night, it is also going on more slowly through the day, 
but is then masked by the much more energetic production of starch. 
The transformation of starch into sugar may possibly be due to the 
presence of a diastatic ferment in the cells of the leaf. 

By an ingenious contrivance the quantity of starch produced and 
converted into glucose was approximately measured. In Helianthus 
annuus 4°64 grms. disappeared in ten hours from 1 sq. m. of leaf- 
surface; and in the same plant 9:14 erms. were formed in the same 
time on the same area. In another case, where the leaves were 
removed from the stem to prevent the return of the starch from the 
leaf to the stem, a sq. m. was found to produce starch at the rate of 
1-648 grm. per hour. As a general result, Sachs concludes that, in 
ordinary circumstances, a leaf may produce in the day from 20 to 25 
erms. of starch per sq. m. of surface; and under certain conditions 
it may even be larger. 


Quantitative Relation between Absorption of Light and Assimi- 
lation.*—T’. W. Engelmann gives the result of a number of observa- 
tions on this point, accompanied by mathematical formule. He 
regards the bacteria-method | as far the most exact for the purpose. 
The general results may be stated as follows :—The absolute minimum 
of absorption lies in the outermost red. Between B and BE, to the 
highest degree at F, lie one or more maxima and minima. The 
amount of absorption increases constantly, attaining its maximum in 
the more refrangible part of the visible spectrum. The amount of 
assimilation corresponds to the amount of absorption in all cases from 
the outermost red to the green; while in the more refrangible part 
the amount of assimilation falls notwithstanding a regular increase 
of-absorption. 


Causes which Modify the Direct Action of Light on Leaves.t— 
Pursuing this subject, E. Mer arrives at the following conclusions :— 
1. The position of leaves is not always an index of their direct 
relation to light; for this sometimes results from influences which 
modify more or less the direct action of light. 
* Bot. Ztg., xlii. (1884) pp. 81-93, 97-105 (1 pl.). 
+ See this Journal, iii. (1883) p. 390. 
us ppomples Rendus, xeviii. (1884) pp. 836-8. Cf. this Journal, iii. (1883) 
p. vd0. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 591 


2. The diurnal sleep of leaves must not always be regarded as a 
result of this action acquired to protect them from too great radiation ; 
for if, in certain cases, either their position or the direction of the 
rays of light is changed, they do not again place themselves in a 
position to be illuminated by the most oblique incidence. 

3. The terms diaheliotropism and paraheliotropism, employed in 
their wide signification, must therefore serve only to indicate the 
positions of leaves in reference to the direction of the rays of 
light, without expressing an opinion on the causes which produce 
them. 


Respiration of Leaves in Darkness.*—G. Bonnier and L. Mangin 
find that, in the case of green leaves growing in darkness, the same 
law of respiration prevails as in organs destitute of chlorophyll, viz. 
that the relationship between the volume of carbon dioxide given off 
and that of oxygen absorbed is constant, whatever the temperature, 
both increasing rapidly with rise of temperature. 


Movements of the Sap in the Root-tubers of the Dahlia. — 
K. Kraus has confirmed the remarkable observation that a tissue with 
acid sap may exude an alkaline fluid or at least one that becomes ver 
rapidly alkaline. The absorption of water by the tubers of the dahlia 
takes place not at all or very slightly through the surface, but 
almost entirely through the roots which are produced in abundance 
in October and November. An abundant “ bleeding” or exudation 
of sap takes place from uninjured leaves and from the axils of the 
leaves ; also from transverse sections, which ceases as soon as the 
tubers are deprived of their roots. 

There is not in the tubers any sharp distinction between the 
medullary rays and the xylem-parenchyma, the mass of the root con- 
sisting mainly of rows of radially elongated parenchymatous cells. 
There are, however, darker portions composed of tracheids surrounded 
by a sheath of thick-walled parenchyma, corresponding to the “ fibre- 
cells” of normal wood. When the tubers are cut off sap exudes 
especially from the periphery of the xylem, most abundantly on 
transverse and tangential sections, and proceeding mostly from the 
closely inclosing parenchyma, partially also from the sieve-tubes and 
pith. That which exudes from the sieve-tubes is alkaline, from the 
wood and pith acid; inulin was also detected in it. The cause of 
this exudation of sap the author regards to be tension of the tissues. 
After the alkaline “bleeding” from wounded tubers has ceased, the 
formation of cork commences on the wounded surfaces. The alkaline 
reaction is probably the result of decomposition. 


Absorption of Water by the Capitulum of Composite.t—A. Bur- 
gerstein notices that the flowers of Composite possess the faculty of 
absorbing water from without through the epidermis; and that the 
under side absorbs water more rapidly than the upper side. 


* Comptes Rendus, xeviii. (1884) pp. 1064-7. 

+ Wollny’s Forsch. aus dem Geb, der Agricultur-physik, vi. (1884). See 
Bot. Centraibl., xviii. (1884) p. 65. 

t Ber. Deutsch. Bot. Gesell., i, (1883) pp. 367-70. 


592, SUMMARY OF CURRENT RESEARCHES RELATING TO 


Measurement of Turgidity.*—H. de Vries applies the term 
“isotonic concentration” to the degree of concentration of different 
solutions in which they attract water with equal force. The strength 
of a solution of potassium nitrate, which has the same affinity to water 
as the solution to be examined of any other substance, is termed the 
“‘nitre-value” of that substance. Representing the attractive force 
of a solution of potassium nitrate at 3, the numbers 2, 3, 4, or 5 
might express that of other solutions. These numbers, representing 
the attractive force for water of a molecule of the substance in ques- 
tion in a dilute aqueous solution, are the isotonic coefficients of the 
different substances. 

The author describes in detail three methods of determining the 
isotonic coefficients of a substance :—(1) The plasmolytic method, by 
placing as similar pieces as possible of the tissue in solutions of 
different concentration of the substance in question and of potassium 
nitrate, and observing the degree to which the parietal protoplasm is 
detached from the cell-wall. ‘This method can be applied in the case 
of only a few plants. (2) The method of plasmolytic transport: by 
measuring under the camera the plasmolysis which occurs on placing 
the preparation in a solution of a salt which causes moderate plasmo- 
lysis; then transferring to solutions of different concentration of 
other salts, and again observing the plasmolysis. (38) The method by 
tension of tissue, by observing the curvature of split terminal por- 
tions of shoots in concentrated solutions of the substance to be 
examined. 

By turgidity the author understands the affinity of the dissolved 
substance for water, and gives detailed results as to the proportion 
of the turgidity due to the different constituents of the cell-sap, the 
most important of these in this connection being sugar, oxalic acid, 
and malic acid. Since the turgidity is constantly being changed by 
substances out of which protoplasm is developed, the inquiry is one 
of great importance in vegetable physiology. As a general rule, the 
author finds the isotonic coefficients nearly to correspond for members 
of the same chemical group. 


B. CRYPTOGAMIA. 


Cryptogamia Vascularia. 


Origin of Roots in Ferns.j—Lachmann has studied the cauline 
fibrovascular system of the ascending rhizome of Aspidium Filia-mas, 
which forms a network of hexagonal meshes, from the periphery of 
which spring the foliar and radical bundles. The former are from 
five to seven in number, one, medio-dorsal, springing from the bottom 
of the network, the others inserted symmetrically on its borders. 


* Pringsheim’s Jahrb. f. Wiss. Bot., xiv. (1884) pp, 427-601; also Vers. Med. 
K. Akad. Wetensch. Natuurk., xix. (1883) pp. 314-27, See Bot. Centralbl,, 
Xvii. (1884) p. 170. 

+ Comptes Rendus, xeviii. (1884) pp. 833-5. 


ZOOLOGY AND BOTANY, MIOROSOOPY, ETO. 593 


The radical bundles are always three in number, one median inferior 
and two lateral, placed symmetrically on the lower half of the net- 
work. The lower radical bundle always springs from the upper 
extremity of a vertical bundle of the stem, inserted on its outer side, 
almost always exactly in the middle, and often a little lower than the 
medio-dorsal foliar bundle. From this point it rises obliquely in the 
cortex, and after passing from 5 to 7 mm. bends, becomes thinner, 
and goes out at the base of the petiole with the roots of which it 
forms the central cylinder. 

This inferior radical bundle is almost always absolutely inde- 
pendent, but this is not always the case with the lateral radical 
bundles. These latter have often a common point of departure with 
the lower lateral foliar bundles, to which they may adhere for a 
length varying from 2 to 4mm.; but the portion of this common 
base which belongs to the radical bundle is generally clearly to be 
distinguished from that which belongs to the foliar bundle, and some- 
times the two bundles are altogether distinct from their insertion. 
These lateral roots behave differently from the inferior root; after 
an oblique course they pierce in the same way the cortex of the 
petiole, the superficial layers of which form a cushion round their 
base. 

The examination of other ferns confirmed the view that in the 
radical bundles we have a simple coalescence of two bundles originally 
distinct. 

In all Polypodiacez the adventitious roots spring from the cauline 
network, and not from the base of a foliar bundle, even in those species 
where, in the adult state, coalescence frequently occurs. 


Monograph of Isoetee.*—L. Motelay and Vendryés publish a 
monograph of the existing species of Isoetesw, founded on the mate- 
rials left by Durieu. 


Systematic Position of Lepidodendron, Sigillaria, and Stig- 
maria.;—B. Renault maintains his previous view as to the relation- 
ships of these fossil organisms, against the objections of Williamson 
and Hartog. He considers that those Sigillarie which can be deter- 
mined with certainty belong to the Gymnosperm type, while the 
species of Lepidophlois have the characteristics of Lycopodiaces. 
The Stigmariz must be regarded partly as rhizomes of Gymnosperms ; 
the anterior portions must have had only leaves with monocentric 
vascular bundles, the anterior part, after the fall of the leaves, only 
adventitious roots with tricentric vascular bundles; while in the 
middle were both roots and leaves. This may serve to explain the 
conflicting descriptions of various writers. 


* Actes Soc. Linn. Bordeaux, xxxvi. (1883) (10 pls.). See Flora, Ixvii. 
(1884) p. 47. 

+ Renault, B., ‘ Considérations sur les rapports des Lépidodendrons, des 
Sigillaires et des Stigmarias, 32 pp. (1 pl.) 1883. See Bot. Ztg., xlii. (1884) 
p. 139. 


594 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Muscineze. 


Variations in Sphagnum.*—C. Jensen discusses the causes of the 
great disposition to vary displayed by the different species of Sphag- 
num, and attributes it, in the first place, to the influence of water, 
and secondarily to variations in the light, temperature, and in the 
nature of the soil. 

When the plant grows completely submerged, all the parts are 
larger and longer; the stem-leaves become iarger, as also do their 
hyaline cells, which are often provided with pores and spiral thicken- 
ings; these leaves then resemble those of the branches in their 
structure. Those branches which depend from the stem, forming an 
envelope round it, lose this structure and grow like the other branches, 
the fertile branches become longer, and are often inserted at a 
greater distance below the apex of the stem; the bundles of the 
branches stand at a greater distance apart. 

Plants growing in a dryer situation are, on the contrary, more 
compact, with shorter stems and crowded short erect branches with 
closely adpressed leaves, as is especially seen in arctic forms. 

When the moss grows in the shade it is of a brighter green and 
stronger growth. 'The fertile branches may be inserted beneath the 
apex of the stem, and are then somewhat elongated. 

Forms sometimes occur with sickle-shaped branches, and others 
which resemble the extra-Huropean species in having the stem-leaves 
of nearly or quite the same structure as those of the branches. These 
usually occur in dry places, but sometimes also in water. 


Fungi. 


Sexual Reproduction in Fungi.j—H. M. Ward gives an elaborate 
résumé of the facts at present known respecting sexual reproduction 
in the various classes of fungi. He points out that—at all events if 
the Basidiomycetes are set aside—the absence of sexual organs 
appears to be in direct proportion to the degree of parasitism deve- 
loped by the fungus. There can be no doubt that the efficacy of any 
act of impregnation depends on some essential difference in the nature 
of the protoplasm of the two cells; that, in an oosphere, for example, 
the molecular energy of the protoplasm is less than that of the rest of 
the plant for the time being, and that the access of the antherozoid 
reinvigorates the sluggish mass, causing the renewal of active life. 
The dormant interval which frequently intervenes between impregna- 
tion and germination may be occupied by molecular rearrangements 
in the mass. The difference in the nature of the male and female 
protoplasm is indicated by the attractive force which the female 
frequently appears to exercise on the male element, as in the case of 
Cidogonium. 'The reinvigorating effect of the male protoplasm may 
last through many generations. The fact of the sexual organs having 


* Bot. Tidsskr. Kjobenhavn, xiii. (1883) pp. 199-210. See Bot. Centralbl., 
xVii. (1884) p. 267. 
t+ Quart. Journ. Micr. Sci., xxiv. (1884) pp. 262-310. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 595 


partially or entirely disappeared in certain classes of fungi may be 
explained on the hypothesis that the very strong development of their 
parasitic character enables them to supply themselves abundantly 
with food-material at the expense of the host, without any very great 
consumption of vital energy, and thus renders unnecessary the re- 
invigoration of the protoplasm, which is the main object of sexual 
reproduction. 


Life-history of Acidium bellidis DC.*—C. B. Plowright has 
experimented on the A%cidium of the common daisy, and considers 
that it is not a mere variety of Aicidium compositarum Mart., but a 
true hetercecismal Uredine, differing from its allies in the time that 
it appears. 


Structure and Affinity of Spheria pocula Schweinitz.t|— Dr. M. 
C. Cooke describes the structure of this species, and shows that it 
must be relegated to the genus Polyporus, to which indeed it was 
formerly referred by Berkeley and Curtis, though the fact appears 
subsequently to have been forgotten. 


Spheroplea.{—Under the designation var. crassisepta E. Hein- 
richer describes a var. of Spheroplea annulina with thicker septa than 
the ordinary form. Hematoxylin revealed the presence of a number of 
nuclei in the cells, sometimes as many as 60, viz. from 1—4 in connection 
with each ring of protoplasm. In the female cells a portion of the 
protoplasm collects round each nucleus to form an oosphere, the 
number of which therefore corresponds to the number of nuclei. The 
formation of antherozoids is accompanied by a great and rapid 
multiplication of nuclei, one nucleus being finally contained in each 
antherozoid, The oospores germinated in the dark, producing swarm- 
spores, from which new individuals sprung, but this latter germination 
was dependent on the presence of light. 


New Parasite on the Silver-fir.$—Under the name Trichospheria 
parasitica, R. Hartig describes a parasitic fungus which has been for 
some years very destructive to the pine-forests in the Neuburger 
forest. The colourless mycelium attacks the young branches and the 
leaves, covering the lower side with a weft of threads, and forming 
blueish white cushions on both sides of the leaves, on which the 
perithecia appear in autumn. ‘The black globular perithecia are 
covered in the upper part with numerous long hairs, and have a 
diameter of 0°1—-0°25 mm., or of 7 mm. including the hairs. The 
asci are about 8:0 » in length, and completely disappear after the 
ripening of the spores. The spores are smoke-coloured, usually 
4-locular, straight, or somewhat curved, and from 15-20 » long. The 
formation of the asci is preceded by that of very small rod-shaped 
cells, possibly spermatia, 


* Journ. Linn. Soc. Lond.— Bot., xx. (1884) pp. 511-2. 

+ Ibid., pp. 508-11 (1 pl.). 4 

t Ber. Deutsch. Bot. Gesell., i. (1883) pp. 433-50 (1 pl.). Cf. this Journal, 
iii. (1883) p. 888. 

§ SB. Bot. Verein Miinchen, No. 13, 1883. See Bot. Centralbl., xviii. (1884) 
p- 62. 


596 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Micrococcus prodigiosus within the Shell of an Egg.*—F. Ludwig 
describes a hen’s egg the albumen of which was throughout of a rose- 
red colour. The absorption-spectrum agreed altogether with that of 
the colouring matter of Micrococcus (Monas) prodigiosus. The fungus 
must certainly have been present in the albumen when in a raw state. 


Photogenous Micrococcus.j{—F. Ludwig has identified the cause 
of phosphorescence in fish with that of the less common phospho- 
rescence of the flesh of animals used for food, especially swine. It 
is due to a mucilaginous substance which can be readily wiped 
off, consisting of micrococci in a state of active motion and 
division, the characteristic form and arrangement of which are very 
readily shown by pigments, especially gentian-violet. The zoogloea- 
colonies are then seen to consist of sharply defined, roundish, densely 
crowded cells, sometimes isolated, more often associated in beautiful 
moniliform threads or compact colonies. The diameter of the cells 
is about 0°5-1 p. To this organism Ludwig gives the name Micro- 
coccus Pfliigeri. It can be readily transferred from the haddock or 
other fish on which it is commonly found, to the flesh of oxen, calves, 
sheep, swine, &c., producing in it the well-known phosphorescence ; it 
occurs also naturally on crustacea, star-fish, &c. 

On the surface of the sea is sometimes found a phosphorescent 
slime, consisting largely of decaying organic matter, the phospho- 
rescence of which is not due to Noctiluca or other animals of that 
kind ; Ludwig attributes it also to this same species of Micrococcus. 


Respiration of Saccharomyces.{—M. Paumés has investigated this 
subject carefully, with the following results:—(1) The respiratory 
activity of the ferment (S. cerevisie) decreases as the temperature 
decreases; (2) in doses of from 1—2 per cent. ether has scarcely any 
effect on the respiration; (8) in doses of from 3-6 per cent. ether 
diminishes and even entirely stops the respiration ; (4) even by these 
doses the plant is not killed. 


Bacillus of Cholera.s—R. Koch has presented to the German 
Government six reports on the cause of cholera-epidemic, as the result 
of investigations on the excreta and on the dead bodies themselves of 
cholera patients in Egypt and in India, and on the inoculation of 
other animals with the germs. The internal organs, lungs, liver, 
spleen, kidneys, &c., as well as the ejecta, were found to swarm with 
microbia of a great variety of kinds; in all cases was found one 
definite kind of bacillus, resembling in size and form that of 
glanders. These were found in largest quantities in the tubular 
glands of the intestines, especially between the epithelium and the 
membrane of the gland. Experiments in inoculating other animals 
with this bacillus yielded only negative results. 


* Zeitschr. f. Pilzfreunde, 1883, p. 176. See Bot. Centralbl., xviii. (1884) 
p. 161. 


+ Hedwigia, xxiii. (1884) pp. 33-7. 

{ Journ. Anat. et Physiol., xx. (1884) pp. 106-15. 

§ ‘ Erster—sechster Ber. an den Staatssecretar des Innern iiber die Arb. zur 
Erforschung der Cholera-Epidemie, von R. Koch.’ Alexandria-Calcutta, 1883-4. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 597 


Observations on Egyptian ophthalmia showed that two different 
diseases are ordinarily included under this name; one caused by a 
kind of bacterium resembling the micrococci of gonorrhcea, the other 
and less severe one by a very minute bacillus. 

The experiments carried on in India determined the presence in 
the intestines, in all cases of cholera, of the same bacillus as that 
found in Egypt; and this Dr. Koch has been able to isolate and to 
cultivate. It then furnished characters in its form and mode of 
growth in nutrient gelatine, by which it is at once distinguished with 
certainty from all other known bacilli. This particular form was also 
never found in the intestines or in the ejecta of those not suffering 
from cholera. Experiments on the infection with it of other animals 
had not, up to the time of the publication of these reports, been 
completely successful. 

The cholera-bacillus is not quite straight, like most other bacilli, 
but is somewhat curved, in the manner of a comma, or even nearly 
semicircular. In cultivation there often arise S-shaped figures, and 
shorter or longer slightly wavy lines. They are endowed with active 
spontaneous motion. They can be best observed in a drop of nutrient 
fluid attached to the cover-glass, which they are seen to swim through 
in all directions. In gelatine they form colourless colonies, which 
are at first close and have the appearance of small fragments of 
glass, but gradually spread through the nutrient fluid. They have a 
tendency to collect at the margin of the drop, where their peculiar 
movements can be well observed, and their comma-like form after 
treatment with anilin-solution. 

As to the question whether their presence is simply due to the 
presence of the choleraic disease which promotes their growth and 
development, or whether they are themselves the cause of cholera, 
Dr. Koch is very strongly of opinion that the latter is the true 
explanation, since they are never found either in the organs or the 
ejecta, except in the case of patients who have either died of or are 
suffering from cholera. They are also found only in that organ 
which is the seat of the disease, viz. the intestines. In the first 
feculent ejecta, the bacilli occur only in small quantities; while in 
the later liquid odourless ejecta, they occur in enormous quantities, 
all other kinds of bacteria being almost entirely absent; they diminish 
in number as the excreta become more feculent, and: have entirely 
disappeared when the patient is completely restored to health. Their 
abundance appears to correspond to the degree of inflammation of the 
mucous membrane of the intestines, attaining their maximum when 
this is of a bright-red colour, and the contents a colourless odourless 
fluid. When the contents become offensive from effusion of blood the 
bacilli decrease in number and are found only in the vesicular glands 
and their neighbourhood. Where death results from a secondary 
complaint following cholera, they are altogether wanting. Their 
behaviour therefore closely resembles that of all other pathogenous 
bacteria, their development being proportional to the severity of the 
disease. 


598 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Virus of Anthrax.*—In a preliminary communication, K. Osol 
describes some experiments, performed in the Pathological Institute 
of Dorpat, by which he claims to have proved that the bacilli which 
occur in anthrax are only to be regarded as the secondary products 
of a chemical virus. 

Recounting the previous observations of Professor Semner and of 
Rosenberger, who claim to have shown the same thing in septiczmia ; 
he states that he himself, in “numerous experiments,” thoroughly 
sterilized, by prolonged boiling, virulent anthrax blood, diluted with 
an equal bulk of water, which was filtered; the residue again treated 
with water, boiled and filtered; the filtrate from both, to insure 
sterilization, was then boiled for two hours on three successive 
days. Of this concentrated viscid anthrax virus, “large quantities ” 
were injected subcutaneously into rabbits and mice, with carefully 
disinfected syringes ; cultivations of sterilized bouillon were at the same 
time inoculated each with “one drop” of the same superheated virus ; 
and at the same time control-animals inoculated with small quantities 
of the same, to demonstrate the absence of micro-organisms. As an 
additional precaution, blood of healthy animals was treated in the 
same manner as the anthrax blood, and similarly injected in large 
quantities into rabbits and mice. 

The animals inoculated with superheated anthrax blood died in 
from 3 to 6 days; in about a fourth of the cases typical anthrax 
bacilli were found in the blood and organs; in the other cases, 
numerous micrococci, as previously found in anthrax blood by 
Semner in 1871, and Bollinger in 1872, and shown by them to be a 
phase of development of the typical bacilli, which has been quite 
recently confirmed by Archangelski. The blood of animals killed by 
inoculation with the superheated anthrax virus, when inoculated into 
sterilized cultivating fluids, developed typical bacilli. Rabbits and 
mice inoculated with it died of pronounced anthrax, in general with 
numerous bacilli in the blood, or, in their place, micrococci and 
“ diplococci,” which, cultivated, developed to anthrax bacilli. The 
blood of these animals similarly was fatally infective. 

In the control experiments, while animals inoculated with “small 
quantities” of superheated virus remained perfectly unaffected, 
cultivations inoculated with similar quantities continued sterile ; hence: 
the author claims to have proved that in anthrax blood there is a 
specific chemical poison, soluble in water, not volatile, of undetermined 
composition, which, inoculated into other animals, so affects the tissues 
of the organism that the innocuous microparasites normally present’ 
therein, develope under its influence, in from 3 to 6 days, to typical 
anthrax bacilli in some cases, and in others to an earlier form of the 
same. 

The control-animals inoculated with superheated normal blood 
were unaffected, save by a slight pyrexia. The author, as he states, 
from these experiments, does not conclude that the bacilli have no 
significance or action in anthrax, but, on the contrary, that they alone 


* Centralbl. f. d. Med. Wiss., 1884, pp. 401-4. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 599 


develope the anthrax virus in the living organism; though they are 
not the primary but the secondary factor, and derive their virulence, in 
the first instance, from the action of an unorganized chemical poison. 
These conclusions are somewhat out of date at the present time, 
and misleading. It has been proved to demonstration that in the case 
_ of anthrax, the organism does, per se, constitute the active contagium. 
The results obtained by Professor Rosenberger, referred to, have been 
shown* to have been due to imperfect sterilization. In those here 
described, the absence of infection with small quantities of the super- 
heated virus, and its occurrence with large quantities, shows evidence 
of the same phenomena; some germs or spores of the bacilli survived 
the boiling, but these were too few in number to be infectious in every 
small portion of the fluid, though they were so in large quantities. 
Were a chemical poison, of which comparatively large quantities are 
requisite, as asserted, the primary factor in infection, the micro-organ- 
isms alone could never be active in unusual quantities, viz. in the 
100-millionth of a drop (minim) as has been shown to be the case. 
The final conclusion of the author here is an obvious paradox, viz. 
that the micro-organism is at once both cause and effect; it alone pro- 
duces the virus—a soluble chemical poison—and is produced by it. 


Attenuation of Virus in Cultivations by Compressed Oxygen.t 
—Experiments were made by M. Chauveau with compressed oxygen 
on the bacilli of anthrax, to ascertain whether their virulence could 
be modified by its graduated action, as by that of heat and other 
agents; with the result, at first, that in the case of guinea-pigs the 
cultivations of the organism exposed to its influence either became more 
actively virulent at moderate pressures, or at high tension completely 
inactive ; but with sheep, by the action of the agent, the cultivations 
are modified in their virulence, so that it is not increased by moderate 
pressure as with guinea-pigs, but on the contrary decreased ; and at 
a point short of that which stops all development of the microbe, 
spores are formed, which, though still fatal to guinea-pigs, are 
innocuous to sheep. 

At this stage of attenuation, however, they produce a temporary 
affection, more or less pronounced, in all the sheep inoculated, which 
passes off within a few days, and the animals are found to have 
acquired immunity from subsequent infection with the most virulent 
material; and that by the single inoculation. 

This modification of virus is transmissible to cultivations of the 
second generation, kept at 36-37° C. under normal pressure, 

It is, too, very remarkable here, that though usually the blood 
of guinea-pigs which have died of anthrax is fatally infective to sheep, 
yet in the case of the former the blood of animals that have suc- 
cumbed to inoculation with cultivations modified by pressure, is 
innocuous to the latter, and moreover confers on them immunity from 
future infection. 

Further, these cultivations are so surely attenuated that no single 


* Proc. Roy. Soc., xxxiv. (1882) p. 150. 
+ Comptes Rendus, xeviii. (1884) pp, 1232-5, 


600 SUMMARY OF CURRENT RESEARCHES RELATING TO 


animal is killed by them, and the protection they confer is complete, 
whilst they preserve their properties for several months, and are as 
effectual with oxen as with sheep. 

Cultivation of the virus of other diseases is equally modified by 
compressed oxygen, as is notably that of swine fever (rouget). 

In conclusion, the author trusts that this method of attenuating 
virus, as yet only tried on a small scale in laboratory experiments, 
may be rendered generally available in practice, with the immense 
advantages it offers of (1) immunity conferred by a single inoculation, 
with (2) perfect safety, and (8) the possibility of using the modified 
cultivations a considerable time after their preparation. 


Rabies.*—L. Pasteur, with the assistance of MM. Chamberland 
and Roux, has a further | communication on this important subject. 

1. if rabic virus is passed from a dog to a monkey, and then from 
one to other monkeys, it gradually becomes weaker. If it is then 
injected into a dog, rabbit, or guinea-pig, it remains in this attenuated 
condition. 

2. The virulence of the poison is increased when it is passed 
from rabbit to rabbit, or from guinea-pig to guinea-pig. If in this 
“ exalted” condition it is passed on to a dog it gives a rabies which is 
always mortal in effect. 

3. Although one can thus increase the virulence of the poison 
by passing it from one to another rabbit, it is necessary to do so 
several times if one is making use of a virus which has been attenuated 
by a monkey. 

Thanks to these observations Pasteur has been able to preserve 
an organism from the effects of more active virus by the use of 
that which is less so. Here is an example:—Virus, made more 
powerful by passage through several rabbits, is inoculated into a dog, 
but as it is inoculated into the dog at every stage of the experiments 
on the rabbits, the result is that the dog becomes entirely refractory 
to the poison of rabies. 

Pasteur proposes to make the following experiments, of which the 
first is the most decisive. He will take twenty of his “refractory ” 
dogs and twenty that have not been inoculated; he will let all be 
bitten by a “mad dog,” and he prophesies that his twenty will escape 
the effects, while the other twenty will exhibit the influences of the 
poison. A similar set of two twenties will be trepanned by the virus 
of dogs & rage des rues; the twenty vaccinated dogs will resist the 
poison, the others will die, either mad or paralysed. In a footnote 
the author points out that of the twenty non-vaccinated dogs, or, as he 
calls them, witnesses, all will not exhibit the effects of the poison to the 
same extent, for rabies does not always follow on the bite of a mad dog. 


Bacteria in Canals and Rivers.{—The much-discussed question as 
to the purification of water in rivers “ by itself,” that is, by the mere 


* Comptes Rendus, xcyiii. (1884) pp. 1229-31. 
+ See this Journal, ante, p. 430. 
t Nature, xxix, (1884) p. 557. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 601 


fact of its motion, seems to have entered into a new phase. Dr. Pehl, 
at St. Petersburg, has recently made a series of bacterioscopic 
measurements on the waters of the capital, which are summed up in 
the last issue of the ‘Journal of the Russian Chemical Society.” The 
water of the Neva itself appears to be very poor in bacteria, namely 300 
germs in a cubic centimetre. After heavy rains this number rises to 
4500, and to 6500 during the thawing of the river. The canals of St. 
Petersburg, on the contrary, are infested with bacteria, their 
number reaching 110,000 in a cubic centimetre, even during good 
weather. The same is true in regard to the conduits of water for the 
supply of the city. While its chemical composition hardly differs 
from that of the Neva (by which they are supplied), the number of 
bacteria reaches 70,000, against 300 in the water taken directly from 
the river; and the worst water was found in the chief conduit, although 
all details of its construction are the same as in the secondary con- 
duits. Dr. Pehl explains this anomaly by the rapidity of the motion 
of water, and he has made direct experiments in order to ascertain 
that. In fact, when water was brought into rapid motion for an 
hour, by means of a centrifugal machine, the number of developing 
germs was reduced by 90 per cent. Further experiments will show 
if this destruction of germs is due to the motion of the mass of water, 
or to molecular motion. The germs, among which Dr. Pehl distin- 
guishes eight species, are not killed by immersion in snow. As 
the snow begins to fall it brings down a great number of germs, 
which number rapidly diminishes (from 312 to 52 after a three 
hours’ fall of snow, on January 21st, 1884), while their number on the 
surface of the snow increases, perhaps in consequence of the evapo- 
ration of snow or of the condensation of vapour on its surface. 


Bacteria from Coloured Fishes’ Eggs.*—Dr. Peter has investi- 
gated the causes of various colouring of the eggs of Coregonus 
Wartmanni, red, blue, and yellowish-brown, and finds it to be due to 
the presence of bacteria, which frequently entirely filled up the 
interior of the egg. The colour itself was due to drops of oil; 
the bacteria themselves were always colourless, and of the following 
kinds :—(1) slender smooth motile rods with short segments; (2) 
thicker motile rods; (3) very thick, straight, smooth, motionless rods 
(rare); (4) very slender, straight, smooth, motionless filaments ; (5) 
micrococci. There was also not unfrequently a Saprolegnia present. 
These bacteria were cultivated in a large number of different nutrient 
fluids, when all transitions from them to a spirillum form appeared ; 
as also a transition from the leptothrix form No.4, to aspirillum. A 
transformation appears to take place of ordinary bacteria into those 
which are the cause of the colouring of the eggs. 


Bacteria connected genetically with Alge.t—H. Zukal has 
continued his investigations { as to the genetic connection between 


* Ber. Bot. Verein Miinchen, Sept. 19, 1883. See Bot. Centralbl., xviii. 
(1884) p. 92. 

+ Oecesterr. Bot. Zeitschr., xxxiv. (1884) pp. 7-12, 49-51. 

t See this Journal, iii. (1883) p. 400. 

Ser. 2.—Von., LV. 28 


602 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Drilosiphon and Leptothriz, from which, in certain circumstances, 
bacteria are produced. The filaments of Leptothrix muralis, which is 
very common in greenhouses, forming a gelatinous deposit on the 
walls, are usually of a light yellow colour; but when, as is frequently 
the case, they grow among tne stems and leaves of mosses, they 
gradually become green. It must therefore be assumed that there is 
always in this species of Leptothrix a certain amount of green 
colouring matter,—another illustration of the difficulty of drawing 
an exact line of demarcation between the Schizomycetes and the 
Schizophycee. It agrees with ordinary Schizomycetes in the capacity 
for assuming bacterium, bacillus, coccus, and vibrio-forms ; and this 
sometimes takes place even with filaments which are distinctly 
reen. 

: When a piece of pure leptothrix-jelly is cultivated under water 
in a giass cell, hormogonia are soon separated, the time of their 
appearance depending on the temperature of the water. These either 
again develope into filaments, or pass into the bacterium form or, 
finally, into the swarming condition. It is usually only the outside 
filaments whieh project from the jelly that develope into hormogonia, 
which either break through the mucilaginous sheath or escape through 
its open end; on their escape they frequently display movements of 
circumnutation, due to the contraction of the protoplasm and not 
to the presence of cilia; the vibrio-form appears, however, to 
possess cilia, though the author was not able to determine their 
presence with certainty. The vibrio-form is developed only from a 
few of the filaments at the margin of the jelly, presenting thus 
a striking contrast to the true Schizomycetes, in which both the 
vibrio and spirillum form-appear suddenly in large quantities, The 
bacterium form of L. muralis exhibits an evident segmentation, espe- 
cially after the application of dilute hydrochloric acid or potassium 
acetate. The hormogonia, when they do not grow into filaments, 
usually break up into bacteria, which then excrete a thick gelatinous 
envelope, and swim on the surface of the culture-fluid, a zoogloea 
family being slowly formed in this way. Less often the bacillus and 
spirillum forms develope zoogloea colonies. Occasionally, by cell- 
division within the jelly, the zoogloea acquires the habit of a palmella 
or merismopezdia. 

The presence of phycochrome is indicated by the motile hormo- 
gonia always collecting on the illuminated side of the vessel. Under 
certain conditions the bacteria swarm out of the zoogloea-jelly, leaving 
their membrane behind; the cell-contents arrange themselves in a 
direction at right angles to the original one, and may develope into 
the bacillus, leptothrix, or spirillum form, then dividing into bacteria, 
&c.; but in all the forms the representatives of the last generation 
are always smaller than the preceding one, finally reaching the limits 
of vision with the best immersion system. 

In addition to the forms above described, Leptothrix muralis much 
less often developes cocci, arranged in a moniliform string, often 
interrupted by a large strongly refringent cell. Filaments are some- 
times found which are segmented above into cocci, below into bacteria. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 603 


The formation of cocci indicates a regression to the nostoe form, 
which is also met with in the history of development of Drilosiphon. 
Resting spores are formed here and there along with the cocci, from 
1-1-8 » in diam.; and these occur also in the bacterium and vibrio 
forms, in very long threads occasionally two. 

The author concluded, as the result of experiments, that Lepto- 
thriz muralis has no power of inducing fermentation or putrefaction. 
The presence of free oxygen is absolutely necessary for its 
growth. It is best cultivated in water containing traces of iron, lime, 
and potash salts. It is probably capable of carrying on an inde- 
pendent existence; but the presence of vigorous tufts of moss is 
apparently favourable to its growth. 

The micro-conditions of the three principal forms of Leptothria 
muralis, the leptothrix form with its hormogonia, the nostoc form, and 
the glceocapsa or palmella form, are morphologically altogether equi- 
valent to true bacteria, but physiologically they are as widely 
removed from them as any green plant from a non-chlorophyllaceous 
saprophyte. 

Action of Oxygen on Low Organisms.*—F. Hoppe-Seyler has 
constructed an apparatus for the purpose of testing the influence on 
the development of the lowest forms of animal life of an abundant 
or restricted supply of oxygen. He finds that in the presence of free 
oxygen the only certainly demonstrable products of the decomposition 
of fluids containing albuminous substances are carbonic acid, ammonia, 
and water. If the fluid is saturated with oxygen, neither hydrogen 
nor marsh-gas makes its appearance ; the ordinary products of decom- 
position, indol and skatol, are not formed at all, leucin and tyrosin 
only temporarily. Microscopic examination shows that when decom- 
position takes place in the presence of abundant oxygen, the Schizo- 
mycetes are formed in much greater quantities than when the supply 
of oxygen is small. The Schizomycetes and Saccharomycetes behave 
in just the same way, from a chemical point of view, as all other 
vegetable organisms, when supplied with abundance of oxygen; they 
absorb oxygen, and give off carbonic acid, water, and ammonia, or 
some nitrogenous substance nearly allied to it. In the absence of 
oxygen all decomposing organisms display fermentation-phenomena ; 
but while the Schizomycetes and Saccharomycetes can remain in this 
condition for a considerable time, all other organisms perish rapidly 
in the absence of oxygen. Certain Schizomycetes can sustain the 
absence of oxygen for a considerable time, especially the one or more 
species which split up cellulose into CO,, C Hy, and H,; but the 
author altogether disbelieves the theory that there are organisms 
which can exist only in the absence of oxygen. 


Biology of the Myxomycetes.t—E. Stahl has made a long series 
of experiments on the cause of the movements of the plasmodia of the 
Myxomycetes, especially of Aithalium septicum. By causing one end 


* Zeitschr. f. Physiol. Chemie, viii. (1884) p. 214. See Naturforscher, xvii. 
(1884) p. 116. 
+ Bot. Ztg., xlii, (1884) pp. 145-56, 161-76, 187-91. 


os: 3 


604 SUMMARY OF CURRENT RESEARCHES RELATING TO 


of a piece of blotting-paper, the other end of which dips into water, to 
come into contact with tan containing plasmodia of the Aithalium, he 
found the latter to display the phenomenon of rheotropism,* i.e. they 
move to meet the current of water, travelling in a horizontal or even 
in a vertical upward direction. The same was observed with the 
plasmodia of a small species of Physarum. The plasmodia display 
not only rheotropism, but also hydrotropism, i.e. movements regu- 
lated by the distribution of water in the substratum, when this water 
is not in motion. During the greater part of the period of develop- 
ment they display positive hydrotropism, or are attracted towards the 
source of water. They are indeed very dependent on water for their 
development. On a uniformly moist substratum in an atmosphere 
saturated with moisture, they spread uniformly in all directions; 
while in a dry air, when the substratum is gradually drying, they 
contract, and Collect in the dampest spots. Negative hydrotropism 
does, however, also occur, where the sporangia bend away from the 
damp spots and stand erect ; this was observed, but only rarely, in 
sporangia of Physarum, Didymium, and Afthalium. 

Various chemical substances, such as crystals of sodium chloride, 
nitre, cane-sugar, grape-sugar, drops of glycerine, &c., exercise a 
repellent effect on the plasmodia. On the other hand an infusion of 
tan produced an opposite attractive result; and to this property of 
moving towards the spots where the supply of nutriment is most 
abundant Stahl gives the name trophotropism. 'The same substance 
may have opposite influences of attraction or repulsion according to 
the degree of concentration of the solution. 

As regards heliotropism, the author adds nothing to the facts 
already known, that plasmodia move from illuminated spots to those 
that are in shade. He was unable to determine satisfactorily their 
relation to geotropism; the vertical position of the fructifications of 
Myxomycetes appears to be due rather to hydrotropism than to 
geotropism. 

With respect to the effect of heat, if Athalium is exposed on the 
two sides to unequal temperatures, an evident motion takes place 
towards the warmer side. 


Lichenes. 


Cephalodia of Lichens.t—Pursuing this subject, K. B. J. Forssell 
states that the alge found in connection with cephalodia belong to 
all the groups of Phycochromacee, including the following families: 
—Nostocacez, Sirosiphonew, Scytonemacee, Chroococcacer, and 
Oscillariacer, the first being the most largely represented. The 
Nostoc cells take up very different positions in relation to the gonidial 
layer of the thallus, belonging to the different kinds of cephalodia 
already described. Occasionally several species of alge are found 
in the same cephalodium. 

The development of cephalodia is always the result of the mutual 


* See this Journal, ante, p. 413. 
t Flora, Ixvii, (1884) pp. 33-46, 58-63, 177-87. Cf. this Journal, ante, p. 100. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 605 


action of hyphe and algal cells; it is not a true parasitism, since the 
alge are not destroyed or weakened by the fungal hyphe ; nor can it 
be regarded as a true example of hypertrophy of the algal cells. 
There is no struggle for existence between alge and hyphe. The 
author was unable to detect the mode in which the algal cells pene- 
trate into the thallus, but each seems to impart nourishment to the 
other. 

The author regards cephalodia as always the result of an acci- 
dental meeting of alga and lichen, the former constituent always 
belonging to a type of very wide distribution ; but there must also 
always be some power of adaptation of one to the other; some forms 
of lichen, as Cladonia, appear never to form~cephalodia. If 
Schwendener’s hypothesis is regarded as one of mutual symbiosis of 
algee and fungi, rather than as one of parasitism, then the occurrence 
of cephalodia supports it rather than otherwise. 


Thallus of Lecanora hypnum.*—kK. B. J. Forssell describes the 
somewhat peculiar structure of the thallus of this lichen. It consists 
of an incrustation of small yellowish-brown rounded granular scales, 
which do not form a continuous layer, but the whole lichen consists 
of a complex of individuals more or less cohering in their growth. 
The scales are of two kinds, one with yellow-green, the other with 
blue-green gonidia. The author is doubtful whether the latter are 
to be regarded as cephalodia, or as belonging to a different lichen- 
species, Pannaria pezizoides. Apothecia occur, on the under side of 
which are sometimes cephalodia containing cells of a Nostoc. 


Alge. 


Systematic Position of Ulvacee.j—The third part of J. G. 
Agardh’s series of Monographs of Algz is devoted to the Ulvacez. | 
Differing from Berthold’s view,t he places the genera Bangia and 
Porphyra among the Ulvacez, and not among the Floridee. In this 
he relies chiefly on the difference of the reproductive organs in the 
Ulvacee and Floridex, the former possessing true zoospores, the 
Floridew antheridia, cystocarps, and tetraspores. The quaternate 
division of the cells in the two genera in question he regards as 
showing an affinity not so much with the tetraspores of Floridex, as 
with the mode of division in Prasiola, Tetraspora, Palmella, Mono- 
stroma, and some species of Ulva and Enteromorpha. There is also a 
very material difference in their physiological value, the octospores 
of Porphyra being regarded as sexual, the tetraspores of the Floridee 
as non-sexual. ‘here is at present a very considerable divergence 
between the description by different writers of the organs of repro- 
duction in Bangia and Porphyra. 

The Ulvacesw are divided by Agardh into eleven genera :— Gonio- 
trichum, Erythrotrichia, Bangia, Porphyra, Prasiola, Mastodia, Mono- 


* Flora, Ixvii. (1884) pp. 187-93. 

+ Agardh, J. G., ‘Til Algernes Systematik ? Lunds Arsskrift, xix. (4 pls.) 
(Latin). See Nature, xxix. (1884) p. 340, 

t See this Journal, iii, (1883) p, 408, 


606 SUMMARY OF CURRENT RESEARCHES RELATING TO 


stroma, Ilea, Enteromorpha, Ulva, and Zetterstedtia. Of these, 
Mastodia and Zetterstedtia are natives of the southern ocean ; Ilea is 
represented bya single species, I. fulvescens, growing at the mouths of 
some Swedish rivers. 


Newly-found Antheridia of Floridee.*—T. H. Buffham briefly 
sums up what is known concerning the reproduction of the Floridez, 
and gives more particular descriptions of the antheridia of species 
not figured by Harvey. 

In Callithamnion tetricum the antheridia appear to be almost 
terminal, and the principal portion of the mass is on the inner face 
of the ramulus, which in the specimen figured is bent down by its 
weight. Call. byssoideum has antheridia that are quite hyaline, with 
the exception of the cellules forming the axis. The antherozoids are 
very elongated, and their attachment can scarcely be made out. In 
Call. Turneri the antheridia cluster thickly on the ramuli, and are of 
ellipsoidal form, colourless, and filled with antherozoids. The 
antheridia of Call. plumula are ramose, and occur in clusters, all 
rising from one cell of the ramulus. 

In Griffithsia corallina the antheridia cluster round the filament 
at the junction of two cells. 

Figures of the foregoing, as well as of the antheridia of Ptilota 
elegans, Ceramium diaphanum, and C. strictum are given by the author. 


New Unicellular Alge.{—P. Richter describes the following 
‘new species of Alge (or Protophyta) :—Protococcus gemmosus, in 
greenhouses, allied to P. cinnamomeus; Dictyospherium globosum ; 
Aphanocapsa Naegelii, in greenhouses ; Aphanothece nidulans, an 
extremely minute species, in greenhouses, along with Protococcus 
grumosus ; Oscillaria scandens, also in greenhouses, possesses a strong 
smell, somewhat resembling patchouli; Scytonema Hansgirgianum, 
in similar situations, allied to S. Hofmanni; Nostoc Wolluyanum. 

The author states further that his Aphanothece caldariorum is the 
bacillus-form of Glaucothrix gracillima Zopf, and is probably identical 
with Aphanocapsa nebulosa A. Br. and Gleothece inconspicua A. Br. 


Structure of Diatoms.t—Count Castracane gives a very useful 
epitome of the chief points in the structure and different modes of 
reproduction of diatoms. 


Belgian Diatoms.§—Dr. H. van Heurck has published the first 
two sets (including fifty species) of slides illustrating his Synopsis 
of Belgian Diatoms, determined and described by A. Grunow. The 
specimens are, for the most part, preserved in the fluid composed and 
described by van Heurck, compounded of styrax and liquidambar, 
which has a higher index of refraction than Canada balsam ; || a few 
in solution of phosphorus. 


* Journ. Quekett Micr. Club, i. (1884) pp. 337-44 (8 pls.). 

+ Hedwigia, xxiii. (1884) pp. 65-9. 

{ Castracane, Conte Ab. Francesco, ‘Generalita su le Diatomee,’ 12 pp. 
Roma, 1884. 

§ Van Heurck, H., ‘Types du Synopsis des Diatomeées de Belgique,’ Serie i. 
ef ii. Anvers, 1883. 

|| Infra, p. 655, 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 607 


Diatomacee from the Island of Socotra.* —F. Kitton gives a list 
of twenty-two fresh-water species from the Island of Socotra. 
Amongst these are a new species of Cerataulus (C, Soctrensis), which 
is the first fresh-water representative of the genus, and Fragilaria 
Ungeriana Grun., which has previously been found in only two 
localities— Cyprus and Belgaum (India). 


—— 


MICROSCOPY. 


a Instruments, Accessories, &c. 


Microscope with Amplifiers.—Fig. 89 shows’ two methods of 
applying a series of amplifiers to the Microscope :—(1) A disk contain- 
ing four apertures is mounted 
above the nose-piece to rotate Fi. 89. 
so as to bring the apertures 
successively into the optic axis. 
One aperture is blank for 
normal examinations; and the 
others are provided with bi- 
concave lenses of 3 in., 4 in., 
and 5 in. negative focus re- 
spectively. This application 
of amplifiers was exhibited at 
the Society several years ago, 
but we have not succeeded in 
tracing the name of the ex- 
hibitor. (2) Mr. J. Mayall, 
jun., suggests that the ampli- 
fiers should be mounted in a 
plate (shown in the fig. ) sliding 
through the body-tube, and 
with means of raising or lower- 
ing it within the body-tube so 
that the best position with each 
objective may be found experi- 
mentally. 

The use of such amplifiers ; 
involves a slight deterioration 
of the quality of the image, but 
in many cases this would be 
more than compensated by the 
increase in the magnification 
and in the working distance. 

Bausch’s Binocular Microscope.t—The following is E. Bausch’s 
specification of his “ Binocular Microscope ” :— 

‘My invention relates to the class of Microscopes in which part 
of the rays of light emanating from the object and passing through 


* Journ. Linn, Soc. Lond.—Bot., xx. (1884) pp. 513-5 (1 pl.). 
t Specification of U.S.A, Patent No. 293,217, dated February 12th, 1884. 


608 SUMMARY OF CURRENT RESEARCHES RELATING TO 


the objective are divided by a doubly reflecting prism, known as the 
‘Wenham prism,’ so that one-half of the rays pass to an auxiliary eye- 
piece mounted in a branch tube applied to the side of the main tube. 

In Microscopes of this class the prism has heretofore been mounted 
in a box arranged to slide laterally in the lower part-of the Microscope- 
body, so that it could be moved into and out of its place by sliding 
the box, and any imperfection in the bearings of the box, which are 
necessarily narrow, allowed the box to move laterally, thereby impair- 
ing the effectiveness of the instrument. Another serious objection 
to the common method of mounting the prism is, that the size of tubes 
in Microscopes being limited, and the box being contained entirely 
in the tube or nose-piece, the movement of the box and size of the 
prism are correspondingly limited. This being the case, a large 
proportion of the rays which are transmitted by modern objectives 
are prevented from passing to the eye-piece, so that it has frequently 
been found necessary to remove the nose-piece containing the ordi- 
nary prism-box and replace it by another nose-piece which had no 
obstruction when the full effectiveness of the objective was desired. 

__ My invention is designed to obviate these difficulties by pro- 
viding a prism-holder with a long cylindrical bearing, which is 
readily made and practically indestructible by wear, and which admits 
of either binocular or monocular arrangement of the Microscope 
with the full effect of either method of vision. 

It consists of a prism-carrying arm fixed to the end of a spindle 
extending through a sleeve passing through the side of the Microscope- 
body, the spindle being provided with a milled head, by which it is 
turned, and with a stop-pin, for limiting its motion. 

Fig. 90 is a vertical section on the line « a in fig. 91 of a portion 
of a Microscope-body, showing my improvement applied. Fig. 91 is 
a plan view, partly in section. 

The body of the Microscope is provided with a nose-piece A, 
threaded in the usual way at its lower end to receive an objective, and 
having sufficient depth to contain the prism-holder B. The prism- 
holder B consists of a metallic plate a, bent twice at right angles, 
and receiving between its parallel sides b c the prism C. The side ¢ 
of the holder B is prolonged, forming an arm c‘ which is secured in 
any suitable manner to the end of a spindle D. In the present case 
it is fitted to a shoulder on the spindle and fastened by means of a 
small nut d fitted to the threaded end of the spindle. The spindle 
D is fitted to a sleeve KE, passing through the side of the nose-piece 
A, so that it may turn therein without lateral or longitudinal motion. 
To insure the perfect bearing of the spindle D in the sleeve E the 
sleeve has a longitudinal slit e, which permits it to adapt itself to 
the spindle by springing and to create the small amount of friction 
necessary to retain the prism-holder in any position. The outer end 
of the spindle D is provided with a milled head F, by which the 
prism may be moved into or out of the field, and a pin /, projecting 
from the spindle through a slot g in the sleeve EH, limits the motion 
of the prism-holder in either direction. The prism-holder B is 
arranged relative to the main and auxiliary tubes of the Microscope 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609 


so that it will swing in a plane lying in the axes of the two tubes, 
and when it is swung down into the position shown in full lines in 
the drawings the prism intercepts one-half of the rays passing 
through the objective and diverts them to the auxiliary tube. When 


Fie. 90. 


the Microscope is used for monocular vision, the prism is turned out 
of the field, as indicated by dotted lines in fig. 90. 

Having thus described my invention, what I claim as new, and 
desire to secure by letters patent, is— 

1. In a binocular Microscope, a swinging prism-holder adapted 
to support the prism within the body of the Microscope either in or 
out of the field of vision, as herein specified. 

2. The combination, with the doubly reflecting prism of a bino- 
cular Microscope, of a prism-supporting arm and spindle attached 
thereto, and extending outward through the Microscope-body, as 
described. 

3. The combination, in a binocular Microscope, of the prism C, 
prism-holder B, spindle D, provided with the stop-pin jf, and the 
slotted sleeve E, as herein specified.” 


Sohncke’s Microscope for Observing Newton’s Rings.*—This 
instrument (fig. 92) is a device of Dr. L. Sohncke for examining 
Newton’s rings, and it is claimed that it fulfils all the conditions in 
regard to variety of movements (and their measurement) necessary in 
such an instrument. 

The microscope-tube (provided with cross threads and magnifying 
20 to 25 times) slides in a short socket H, the former having a scale 
in half-millimetres (with a nonius on H) for allowing the exact 
position to be read off. The socket, with the Microscope, can be 
turned on a horizontal axis, fixed in the front part of two brass 


* Zeitechr. f. Instrumentenk., i. (1881) pp. 55-8 (1 fig.). 


610 SUMMARY OF CURRENT RESEARCHES RELATING TO 


shoulders h, rising from a common base plate. On one side the axis 
carries a quadrant turning with the Microscope, and having one 
arm parallel with the optic axis of the Microscope. A plumb line 
gives the angle on the quadrant. On the other side of the axis is 
a serew-nut to clamp it in any desired position. The brass base plate 
to which the shoulders h are attached, slides by means of a screw M, 
in a second piece shown in the figure. The motion is at right angles 
to the plane of incidence of the light falling on the object, i. e. from 
right to left (or vice versd) as the observer would stand in using the 
instrument. The second piece is again part of another slide, which 


Fic. 92. 


“a 
Ca? 


(oa | 
i oa HAAG A | | 


is moved backwards and forwards by the screw M,; the motion here 
is at right angles to that of the first slide, and therefore parallel to 
the plane of incidence. The extent of these two movements is read 
off on two millimetre scales on the guides of the slides, and the 
screw heads are divided for reading fractional parts of mm. The 
heavy iron base G of the whole instrument rests upon three feet, 
and the plane and convex glasses g are laid upon a small stage T 
attached to the front of the instrument, and capable of being raised 
and lowered above G as required. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 611 


Although the apparatus in this form may be thought to fulfil all 
requirements, Dr. Sohncke considered it especially necessary to add 
an additional contrivance for indicating, without further measure- 
ment, the most characteristic phenomenon in the position of Newton’s 
rings, viz. that those ring-points which are in the plane of incidence 
passing through the centre of the rings, all lie in a straight line 
which rises obliquely towards the light. The greatest inclination of 
this “fundamental line” towards the horizon is 19° 28’. If we have 
an arrangement by which the Microscope with any angle of incidence 
can be given a movement parallel to the “fundamental line,” then 
when any one ring (in the central plane of incidence) is clearly seen 
by proper focusing of the Microscope, all the rings in succession will 
also be clearly seen by the movement in question ; whilst if the Micro- 
scope were moved horizontally, they would very soon be out of focus. 
This requirement is carried out in the present instrument by the 
guides of the lower slide being fixed, not upon the horizontal base G, 
but upon the plate P, which is movable on an axis at right angles to 
the plane of incidence, and can be fixed at any required inclination 
between 0° and 20°. That the object may not be disturbed by the 
inclination of the plate, it is cut out somewhat in the shape of a 
horse-shoe. To use this arrangement the plate P must be placed at 
the angle w» of the “fundamental line” for the particular angle of 
incidence 6. The value of w is obtained from the formula :— 


sin @ . cos @ 


tgwo= 


The Microscope is then to be placed at the required angle of 
incidence. In order to do this direct, a plumb line, instead of an 
index, is used for reading off the “angle” on the quadrant, as an 
index would join in the inclination of the plane P. The lower 
slide has now only to be moved parallel to the plane of incidence, by 
means of the screw M.,, in order to see all the rings pass across the 
field in complete distinctness. 

Dr. J. H. L. Flégel describes* a method of determining the thick- 
ness of diatoms by the examination of the Newton rings formed when 
they are illuminated by reflected light from a Lieberkiihn, It con- 
sists simply in tilting the slide at an angle, the light being admitted 
to the Lieberkiihn through a small excentric aperture in the dia- 
phragm, reaching the objective only after reflection from the prepara- 
tion. 


Harris & Son’s Portable Microscope.—This (figs. 93 and 94) is 
a somewhat ancient form, probably fifty years old, but is arranged 
on an ingenious plan to secure portability. When set up for use it 
takes the form shown in fig. 93. By unscrewing the tube, and 
screwing it into the lower side of the ring which holds it, and closing 
the tripod legs together, it is reduced to the form shown in fig. 94. 


* Arch. f. Mikr, Anat., vi. (1870) pp. 472-514, 


612 SUMMARY OF CURRENT RESEARCHES RELATING TO 


The subsidiary leg, which carries the mirror, folds against the leg 
of the tripod to which it is attached. The stage is removable, leaving 


Fie. 93. 


Last 


ine —_— 
FN 


a ring, which is attached by three supports to the tripod, and rises 
and falls somewhat as the tripod legs are shut or opened. 
The instrument is hardly so convenient as the modern forms which 


Fig. 94. 


have been devised in such profusion, but it is interesting as being a 
very early progenitor of this class of instrument. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 613 


Seibert’s No. 8 Microscope,—The Micro- Fig. 99. 
scope No. 8 in Seibert and Kraft’s Catalogue i 
(fig. 95) has a fine adjustment similar in 
principle to those described Vol. III. (1880) 
p. 882, though carried out in a different man- 
ner. Here the stage is supported on a horse- 
shoe-shaped frame, and is pivoted to one of 
the projecting arms. A screw passing through 
the opposite arm raises the stage at the end 
and as the screw is withdrawn a spiral spring 
presses the stage back again. 


Reichert’s Large Dissecting Microscope 
and Hand Magnifiers—C. Reichert’s large " | 
dissecting Microscope (fig. 96) is of excep- ag 
tional size for the examination of sections of — = 
brain and similar large objects. The stage 
is entirely of glass, and is 11-5 cm. wide and 
18 cm. long. The mirror can be moved for- 
wards and to both sides. The preparation is 
intended to be fixed while the lens is capable 
of being moved over it in all directions. The 
arm a b can be rotated on a, and the lens- 
carrier c d can also be rotated at b. By turning 
the milled head « the inner tube d which carries 
the lens is pushed forward or withdrawn again. 


614 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Herr Reichert also mounts two doublets of 10 and 20 power in a 
nickelled frame (fig. 97, natural size). When not in use they are 


Fig. 97. 


ie REICHERT WIEN 2 
— 


IML 


turned back within the frame, or for examining an object, brought out 
as shown in the fig. 

Geneva Company’s Dissecting Microscope.—This, fig. 98, con- 

sists of two parts, a support for the lenses and a stage and mirror. 


The two are quite separate, a plan which gives more freedom of action 
than can be obtained in the ordinary form of dissecting Microscope. 

The lens-support can be raised by a pinion acting on a rack on an 
inner tubular pillar. It can also be rotated in a horizontal plane on 
the top of the latter or in a vertical plane on the pivot clamped by the 
second (upper) milled-head. 

The stage has side rests for the hands and can be screwed to the 
top of the box holding the instrument. The mirror is rotated on its 
axis by the milled-head shown on the right. On one side there is an 
ordinary concave mirror and on the other a plane one of opal glass. 


Drallim and Oliver’s Microscope Knife— The following is taken 
from the advertisement of this knife (fig. 99) :— 

“ It comprises a great variety of articles including a large dagger- 
blade, small penknife, pair of folding scissors, corkscrew, nail-trimmer 
and file, tortoise-shell toothpick and ear-scoop, nickel silver tweezers, 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 615 


and last, but by no means least, a very powerful Microscope. We are 
not aware of any other knife manufactured which contains a Micro- 
scope of any description, and we anticipate an enormous demand in 
consequence. An ordinary pocket handkerchief submitted to the 


lens of this powerful glass, the texture appears nearly as coarse as a 
sack. Scientific students and merchants will find this invaluable to 
them, as the knife is of convenient size to be carried in the waistcoat 
pocket.” 


Ward's Eye-shade.*—Dr. R. H. Ward’s device consists (fig. 100) 
of a circular disk of hard rubber or blackened metal, about 14 in. in 
diameter, an extension of which in the form of a band 1/2 in. wide 
crosses in front of the nose of the observer, but quite out of the way, 
and encircles the top of the 
draw-tube or compound body Fic. 100. 
just below the ocular. As now 
used, this shade is made of hard 
rubber, which is of light weight, 
and suitably dark colour, is 
less likely than metal to 
scratch the brasswork with 
which it comes in contact, and 
is so elastic as to be applicable to a considerable variety of tubes. 
The same shade, for instance, can be used on tubes of from 1 to 1} in., 
or from 1/8 to 13, the best fit being of a size midway between the two 
extremes. Besides this easy range of adaptation, this eye-shade differs 
from those hitherto in use in its attachment to the body instead of 
the ocular, by which it is brought to an advantageous distance from 
the face, and is retained in position as long as the instrument is in 
use, instead of being removed with the ocular and requiring a fresh 
application every time that is changed. It is reversible by simply 
turning it over, and can thus be instantly transferred from the left 


* Amer. Mon. Micr. Journ., y. (1884) pp. 82-3 (1 fig.). 


616 SUMMARY OF CURRENT RESEARCHES RELATING TO 


to the right eye, according to the observer's custom of using either 
eye habitually or both in succession. It is equally applicable to 
stands whose construction does not admit of its being slipped over the 
tube from the top; the spring ring at the right of the figure being 
in such cases made partly open so as to spring on from the side. 


Endomersion Objectives.*—Prof. K. W. Zenger claims to have 
found that perfect achromatism of telescope and Microscope objectives 
is possible by using a mixture of ethereal and fatty oils, the dispersive 
power of which for the different rays of the spectrum increases regu- 
larly. The disadvantages of the use of fluids are obviated by mixing 
with suitable salts of the fatty acid series by which nearly hard or 
gelatinous, vitreous, homogeneous, colourless, and transparent sub- 
stances are obtained. 

The following are extracts from two papers published by the 
author :— 

The construction of achromatic objectives for telescopes, M’<cro- 
scopes, and photography has, from the beginning, presented great diffi- 
culties theoretically as well as practically. The dioptrical formule 
which give the equations for the achromatism and aplanatism of the 
objectives are so complicated that, up to the time of Fraunhofer and 
the younger Herschel, opticians were content with developing the 
conditions of achromatism and aplanatism in the axis. In this way, 
however, a perfect objective was theoretically not to be obtained, and 
therefore the best makers of that time were obliged to confine them- 
selves to experimental trials. 

Herschel and Fraunhofer first showed the way to a more accurate 
determination of the direction of the rays, and the former has given 
us a complete theory of telescope objectives, but for the much more 
difficult computation of Microscope objectives almost nothing has 
been done, and we to-day still look for a theory of these objectives. 

The principal practical difficulty for all kinds of objectives lies in 
procuring suitable refracting media, because the flint and crown glass, 
hitherto exclusively used, deviate greatly from the conditions of 
perfect achromatism. Blair, at the end of the last century, showed the 
possibility of getting rid of all colour by the use of at least three 
refracting media, crown glass, oil of turpentine, and naphtha, which 
give contrary secondary spectra, the dispersive power of one being 
greater in the red, and of another in the violet part of the spectrum. 
In this way he succeeded in making an absolutely achromatic 
objective, the aperture of which was particularly large, namely, one- 
third of the focal length. 

After Blair the matter was lost sight of until the second decade 
of the present century, when Barlow made an objective of crown 
glass and a biconcave lens filled with bisulphide of carbon on the 
dialytic principle. The achromatism of this was not, however, 
perfect, Blair’s use of more than one fluid not having been attended 
to, and the question again fell into oblivion. 


* SB. K. Bohm. Gesell. Wiss. Prag, 1881, pp. 479-92, 467-79 (reversed in 
order). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO, 617 


Prof. Zenger, in view of Blair’s experiments, determined to see 
whether it would not be possible to find fluids which in combination 
with crown glass, would produce achromatic objectives. The con- 
ditions for absolute achromatism require that the partial dispersions 
should maintain the same relation in all parts of the spectrum for the 
two refracting media. Now mixtures of aromatic and fatty substances 
possess this property to a high degree of approximation, so that when 
combined as lenses with crown glass (a biconvex crown and a plano- 
concave fluid) all the different rays of the spectrum will be united 
and a perfection of achromatism will be produced not hitherto 
attained. 

The question of course arises whether the fluids. in consequence 
of striz-formations, through rapid changes of temperature, may not 
originate a new element of optical imperfection. This is opposed to 
the author’s experience of fluid achromatics in sunlight, either with 
the telescope or Microscope. He has succeeded in converting the 
ethereal and fatty oils which serve for the production of the refract- 
ing media, into the condition of vitreous bodies, or into a kind of 
gelatine in which striz-formation is not as easily possible as in very 
mobile fluids. 

By solutions of stearic, oleic, or palmitic acid, or mixtures of 
these, we can change benzol, castor-oil, poppy-oil and other similar 
ethereal and fatty oils into transparent gelatine, which is amorphous 
like glass, perfectly clear and does not flow out of the vessel if in- 
verted. These substances are already used in the arts. 

An immense scope for combination is thus opened in order, so to 
say, to produce kinds of glass of any desired refraction and dispersion, 
and consequently the optician is saved the trouble of undertaking 
changes of radius at great expense and loss of time. It is sufficient 
to make a suitable selection of the gelatine substance which is to 
be inclosed between a plane parallel plate and the biconvex lens, in 
order to solve the hitherto difficult problem of a perfect achromatic 
and aplanatic lens-combination. 

The closing up of the fluid must be as hermetical as possible, in 
order to prevent any evaporation and chemical change in the course 
of time. There are ethereal and fatty oils which are transparent and 
very little changeable. 

The problems as to lenses for telescopes, Microscopes, and photo- 
graphic objectives are therefore, it is claimed, extraordinarily 
simplified through the use of “endomersion” objectives, which are 
thus named by the author in analogy with immersion objectives, 
because the fluid is between the lenses. On account of the fact that 
three radii are equal, while the fourth is infinitely great, he also 
calls them “symmetrical” endomersion objectives, a quality which 
embraces the most favourable conditions for brightness, sharpness, 
and flatness of field of view. 

Formule and tables are given for the construction of endomersion 
objectives, and after considering more particularly the case of teles- 
cope objectives, those for the Microscope are dealt with, in which case 
the plane side of the concave fluid lens should be turned to the object. 


Ser. 2,—Vou, LV. 2T 


618 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Such an objective is then somewhat over-corrected, and thus exactly 
suited for a Microscope objective, because in the case of a single lens 
the over-correction can be removed by the Huyghenian ocular, while 
with doublets and triplets, the lens can be corrected or over-corrected 
to the desired amount, the residue being removed by the ocular as is 
commonly done by the Lister method. : 

When the necessary calculation for a given mean refractive and 
dispersive relation, such as from quartz to a fluid, is once made for a 
fixed large angle of aperture and a given thickness of the lens, it is 
easily seen what alterations a change in the refraction of. the less 
refracting lens requires, according to the crown glass used, and we 
can correct the objective accordingly. 

An objective, composed of three achromatics, whose curves were 
calculated for parallel rays (according to the formule and tables of 
the author) gave such satisfactory results that further detailed 
calculation is only required for exceptionally large angles of aperture. 

The performance of a triplet of 8 mm. equivalent focus composed 
of three symmetrical endomersion lenses consisting of crown glass 
and a mixture of fatty and aromatic substances, gave perfect achro- 
matism, for when achromatic eye-pieces (by Schréder) were used 
which magnified 9, 18, 36, and 72 times, there was even with the last, 
in bright lamplight and sunlight, scarcely a trace of colour on 
diatoms or on a Zeiss’s silver grating, whilst all the objectives at 
hand * showed all the colours of the spectrum with such enormous 
eye-piece power. 

With some of these objectives, however, the aplanatism was more 
perfect than others, which can probably be accounted for by slightly 
imperfect centering of the three lenses, and also by the defective 
quality of the plane-parallel plates, in place of which, later on, con- 
cave lenses of great focal length were used. 

In direct light, with an angle of aperture of only 56°, all the 
more easy diatoms of Moller’s plates were resolved, and of the more 
difficult the following :—Fhabdonema arcuatum and R. adriaticum, 
Achnanthes subsessilis, Scoliopleura convexa (the images appear black 
upon white). 

With oblique light :—WNitzschia circumsata, Navicula divergens, N. 
minor, Gomphonema geminatum, Melosira Borrerit, Symbolophora Trini- 
tatis, Odontodiscus subtilis, Hyalodiscus stelliger, and H. subtilis could 
not be quite resolved, as they were on the limits of the unresolvable 
with the aperture. Grammatophora marina and Pleurosigma angu- 
latum were not resolved. 

A double symmetrical endomersion objective, combined after the 
manner of Steinheil’s “ Symmetric Aplanaten,” gave no trace of a 
difference of the chemical and visual foci, and therefore such an 
objective, which can be constructed from quartz and a very transparent 
fluid, is of practical importance for photography. 

The usual contrivance is not necessary for obtaining sharp photo- 
graphs of diatoms, which will even bear well a power of 30 times as 

* Objectives by Schneider of Berlin, 1” to 2” dry, and 3—+,, (sic) immersion, 


by Zeiss 1 n (A) and Hartnack, as well as Reichert of Vienna. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 619 


microscopic objects, furnishing the best proof of the coincidence of 
the optic and actinic foci. The eye-piece is removed and the camera 
placed in position, without having to make use in any way of coloured 
or subdued light for the illumination. 

In an abstract * of Prof. Zenger’s papers by G. Fischer, he expresses 
the apprehension that the unavoidable changes of temperature to 
which the lenses would necessarily be subject would be likely to im- 
pair their efficiency, and adheres to his own view that absolute 
achromatism will in all probability only be obtained by the discovery 
of more favourable kinds of glass. 

Prof. Zenger subsequently wrote t to Herr Fischer that Merz’s 
crown glass is still much wanting as regards refraction and disper- 
sion; in his view crown and flint never give a rational dispersion, 
although flint containing different quantities of lead approximates 
to it. Incomparably better is the achromatism obtained by his fluid 
lenses, which are as much in advance of the best achromatics of the 
present time as these latter are in advance of the non-achromatics. 
The analogy of the eye, which formerly led to the discovery of 
partial achromatism, prompted him to try and obtain absolute 
achromatism by imitation of the gelatinous fluids of the eye, that is 
by mixing two, three, and four different fluids. In this he has 
succeeded ; two or three fluids, oil and balsam mixed, give, compared 
with crown glass or quartz, quite rational spectra; that is constant 
ratio of the partial dispersions. A constant dispersion-quotient can 
be obtained for the whole length of the spectrum within 0:002 to 
0-004, therefore much better achromatism than with the best of 
Merz’s systems, in which the quotients differ from 0°004 to 0°026. 

Finally he points out that the experiences of photography suffice 
to show how much the best productions of the first modern opticians 
fail in collecting all the rays to one focus. He, on the contrary, is 
able with his fluid system to obtain micro- and astrophotographs 
without the interposition of coloured glasses or adjustment-correction, 
just as if his lenses were mirrors ; consequently, all rays, chemical and 
optical, are united in one focal point. 

Prof. Safarik has pointed out { to Herr Fischer that whilst with 
Zenger’s objectives perfect achromatism is undoubtedly almost attain- 
able, yet it is very doubtful whether aplanatism (removal of spherical 
aberration) is also attainable. With Merz the diminution of the 
dispersion-relation necessarily entails a lengthening of the focus, the 
reverse of what opticians have hitherto striven to obtain. ‘‘ Whether,” 
adds Herr Fischer, “ Zenger’s system, the three-lens system (Merz’s), 
the improved Herschel-Fraunhofer system with more perfect kinds of 
glass, Pléssl-Littrow’s, or an entirely new system, attains the desired 
end, this much may, 1 consider, be confidently expected, that sooner 
or later a considerable improvement of the achromatism, and with it 
of the optical capacity of the Microscope and telescope, will be assured, 
In conclusion, I gladly avail myself of the opportunity of bringing 


* Central-Ztg. f. Optik u. Mech., iv, (1883) pp. 254-6, 
+ Ibid., p. 267. 
t Ibid. 


272 


620 SUMMARY OF CURRENT RESEARCHES RELATING TO 


forward the opinion of so competent a judge as Dr. L. Dippel,* 
against that of Prof. Merkel, who has objected to Merz’s object- 
glasses that they get dim from being too soft. Dr. Dippel writes: ‘I 
have lately become more closely acquainted with Merz’s objectives, 
1/3, 1/9, 1/12, 1/18, and 1/24 in., and have convinced myself that 
the objection made to them by Prof. Merkel of their being affected 
by the air is not well founded.’ ” 


Selection of a Series of Objectives—At p. 449 (last line but 
one) a misprint occurs of 200° instead of 120° as in Dr. Carpenter’s 
original text. 


Correction-Adjustment for Homogeneous-Immersion Objectives. t 
—Dr. W. B. Carpenter’s views on this somewhat vexed question 
are explained in his article ‘“‘ Microscope’ in the ‘ Encyclopedia 
Britannica.’ 

After pointing out that with homogeneous-immersion objectives 
the microscopist can feel assured that he has such a view of his object 
as only the most perfect correction of an air-objective can afford, 
Dr. Carpenter continues as follows: “This is a matter of no small 
importance, for while in looking at a known object the practised 
microscopist can so adjust his air-objective to the thickness of its 
cover-glass as to bring out its best performance, he cannot be sure, in 
regard to an unknown object, what appearance it ought to present, 
and may be led by improper cover-correction to an erroneous conception 
of its structure. 

“Tt has been recently argued that, as the slightest variation in 
the refractive index of either the immersion fluid or the cover-glass, 
a change of eye-pieces, or the least alteration in the length of the 
body—in a word, any circumstances differing in the slightest degree 
from those under which the objective was corrected—must affect the 
performance of homogeneous-immersion objectives of the highest 
class, they should still be made adjustable. The truth of this con- 
tention can, no doubt, be proved, not only theoretically, but practi- 
cally, the introduction of the adjustment enabling an experienced 
manipulator to attain the highest degree of perfection in the exhibition 
of many mounted objects, which cannot be so well shown with 
objectives in fixed settings. But it may well be questioned whether 
it is likely to do the same service in the hands of an ordinary working 
histologist, and whether the scientific investigator will not’ find it 
preferable, when using these objectives, to accept what their maker 
has fixed as their point of best performance. The principal source of 
error in his employment of them lies in the thickness of the optical 
section of the object ; for the rays proceeding from its deeper plane, 
having to pass through a medium intervening between that plane and 
the cover-glass, whose refractive and dispersive indices differ from 
those of the glass and immersion fluid, cannot be brought to so accurate 
a focus as those proceeding from the plane immediately beneath the 
cover-glass. The remedy for this, however, seems to be rather in 


* ‘Das Mikroskop,’ 2nd ed., 18838, p. 460. 
+ Encyclopedia Britannica, 9th ed., xvi. (1883) p. 265. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 621 


making the preparation as thin as possible than in the introduction of 
what is likely, in any but the most skilful and experienced hands, to 
prove a new source of error. Every one who has examined muscular 
fibre, for example, under a dry objective of very high power and large 
aperture, well knows that so great an alteration is produced in its 
aspect by the slightest change in either the focal adjustment or the 
cover-correction that it is impossible to say with certainty what are 
the appearances which give the most correct optical expression of its 
structure. This being a matter of judgment on the part of each 
observer, it seems obvious that the nearest approach to a correct view 
will be probably given by the focal adjustment of the best homogeneous 
immersion-objectives, in fixed settings, to the plane of the preparation 
immediately beneath the cover-glass.” 


Lighton’s Immersion Illuminator.*—This device of W. Lighton 
(fig. 101) consists of a small disk of silvered plate-glass c, about 1/8 in. 
thick, which is cemented by glycerin or some homogeneous-immersion 
medium to the under surface of the glass slide s, r being the silvered 
surface of the disk, b the immer- 
sion objective, and / the thin glass Fic. 101. 
cover. The ray h from the 
mirror or condenser above the 
stage will enter the slide, and 
thence be refracted to the sil- 
vered surface of the illuminator r, 
whence it is reflected at a corre- 
sponding angle to the object in 
the focus of the objective. A shield to prevent unnecessary light from 
entering the objective can be made of any material at hand by taking 
a strip 1 in. long and 3/4 in. wide, and turning up one end. A hole 
of not more than 3/16 in. in diameter should be made at the angle. 
The shield should be placed on the upper surface of the slide so that 
the hole will cover the point where the light from the mirror enters 
the glass. “ With this illuminator Méller’s balsam test-plate is 
resolved with ease, with suitable objectives. Diatoms mounted dry 
are shown in a manner far surpassing that by the usual arrangement 
of mirror, particularly with large angle dry objectives.” 


Illumination by Daylight and Artificial Light—Paraboloids and ~ 
Lieberkiihns.t—E. M. Nelson finds daylight effective for low powers 
up to 2/3 in., and with condenser up to 1/6 in. Direct sunlight 
involves the use of a heliostat, otherwise the continued adjustment 
of the mirror is irksome. Where strong resolving power is needed, 
oblique pencils of sunlight from the heliostat outrival any other 
illumination ; but much care is necessary not to injure the sight, and 
on the whole, he cannot recommend its general use except for photo- 
graphing. Diffused daylight is too uncertain and too variable for 
accurate testing of objectives. It is not possible to get with diffused 
daylight the absolutely best image that an objective will produce. 


[]% 


* Amer. Mon. Micr. Journ., vy. (1884) pp. 102-3 (1 fig.). 
+ Engl. Mech,, xxxix. (1884) p. 48. 


§22 SUMMARY OF CURRENT RESEARCHES RELATING TO 


A really critical image could only be seen with artificial light, and 
with a good condenser and diaphragms. He does not mean to say 
that no good work can be done with diffused daylight, for excellent 
work is done with low or medium powers; but he insists that it is not 
possible to do any such critical work as testing objectives by daylight 
as thoroughly as it can be done by artificial light. With daylight and 
mirror only there is milkiness and “ glaze.” 'The milkiness can be 
got rid of by a diaphragm, and the “ glaze” by using a ground glass 
behind the object. Unless a condenser is used there will always be 
found a falling off in the quality of the image with all powers higher 
than 2/3 in. From long experience in working with the Microscope, 
he feels justified in asserting that on the whole daylight is more trying 
to the sight than lamplight. 

The oxy-hydrogen light may be serviceable for resolving such 
tests as Nobert’s lines, but the incandescence lamp he regards as 
entirely a failure for microscopical purposes. “This is at once 
obvious upon the consideration that the finest images seen are got by 
viewing objects, as it were, in the image of the source of light. All 
critical images of transparent objects viewed by direct transmitted 
light require first that the source of light should be pictured by the 
condenser exactly in the plane of the object, the object then serves 
to interrupt the image of the source of light. The observer has simply 
to arrange the lamp, condenser, and diaphragms so as to produce the 
most perfect image of the source of light of the required size in the 
plane of the object, the objective will then have fair play. The size 
of the image of the lamp flame can be controlled by distancing the 
lamp. There is no other secret in the matter. With the incandescent 
lamp the image produced by the condenser represents the mere 
carbon thread, on which no object could be seen projected ; in order 
to obtain some extent of brightly luminous field, the condenser must 
be put out of focus, then the intensity of the light is so reduced that 
the observer would simply discard the incandescence, finding it far 
less serviceable than a shilling paraffin lamp.” 

He entirely condemns the use of paraboloids for dark-ground 
illumination, as properly adjusted central stops with the condenser 
will give by far the best dark-ground illumination. For opaque 
objects he considers nothing has been devised so good as Lieberkiihns, 
and objects ought as far as practicable to be mounted for use with 
Lieberkiihns, and not covered up with paper. If the side illuminator 
is used it should be attached to a fixed part of the stand, not to the 
body-tube or stage. 

With the preceding remarks may be contrasted the view of 
Prof. Abbe (in litt.) that it is quite immaterial, from a theoretical 
point of view, whether an illuminator has or has not spherical 
aberration. The effect of illumination does not depend upon the 
projection of a sharp image of the source of light upon the object, nor 
even on the projection of any image at all. The only object of pro- 
jecting an image of the source of light approwimately at the plane 
of the object is in order that a uniform illumination of a given area 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 623 


of the object (the field of vision) may be obtained by means of a small 
source of light. This object is attained notwithstanding considerable 
aberrations, and it is the better obtained the greater the focal length 
of the illuminating system. A lens of 3/4 in. curvature is therefore 
less advantageous than one of 1 in. 

The general view of English microscopists is undoubtedly in 
favour of the superiority of an achromatic condenser over any non- 
achromatic arrangement. With the latter, confused pencils of light 
are produced by the spherical aberration, which seriously impair the 
images of fine structures, whilst with the former, “the most delicate 
objects are seen with a clearness and sharpness of detail quite 
unknown to those microscopists whose experience has been confined 
to the use of non-achromatic condensers.” * 


Bausch’s New Condenser.{—E. Bausch describes a new condenser 
(figs. 102 and 103), similar to thaf of Prof. Abbe, the formula upon 


Fie. 102. Fie. 108. 


i 


T TTT | 
‘nT 


Tl 


which it is constructed being, however, a modification of that used in 
Bausch’s Immersion Illuminator. The posterior system is as large 
as the substage-ring will allow, and will transmit and condense all the 
rays which pass through thisfrom the mirror. Its numerical aperture 
is about 1-42. 

There are two styles of mounting, fig. 103 shows the substage 
adapter and condenser with a swinging diaphragm ring between them. 
This ring receives the various stops, which may be changed without 
disturbing the condenser. Fig. 102 is intended to give the different 
degrees of oblique illumination, from central to that of the utmost 
possible limit. It is provided with a circular opening, 1/4 in. in 
diameter, which may be decreased if desired, and which is caused to 
move slowly from the centre to the edge of the mounting by turning 
the outside milled edge. 

Both of these mountings are adapted to substages attached either 
to the substage bar, or fixed to the bottom of the stage. The condenser 
is also furnished with plain substage adapter only. 


Glass Frog-plate.—This (fig. 104, designer unknown) is a simpli- 
fication of the ordinary frog-plate. The general form of the 


* Swift’s ‘ The Microscope,’ 1883, p. 43. 
+ The Microscope, iy. (1884) pp. 105-6 (2 figs.). 


624 SUMMARY OF CURRENT RESEARCHES RELATING TO 


old brass plates is retained, but in place of brass glass is used, the 
edges of which are serrated for the string. The brass pin is at 


Fie. 104. 


present only cemented to the plate; it would be better if it passed 
through it. 

Groves and Cash’s Frog-trough for Microscopical and Physio- 
logical Observations.—Some years since Mr. J. W. Groves devised a 
simple guttapercha trough, in which circulation in the webs of frogs 
could be observed for a considerable time without the web becoming 
dry. This was efiected by keeping the feet of the frog entirely 
covered with water, into which the objective (protected by a water- 
tight cap closed below by a piece of thin glass) could be lowered 
after the fashion of Mr. Stephenson’s submersion objective. This 
contrivance he and Dr. Theodore Cash have considerably improved. 
The trough (fig. 105) is long enough to admit a full-sized frog ; in 


Fic. 105. 


_—— 


Men 


U 


the bottom, which is lined with cork, are two windows of glass, through 
which light may be transmitted to the webs of the feet. At the 
anterior end is a projection, with a cork bottom and glass window for 
the examination of the tongue, and another similar projection at the 
side for the observation of the mesentery or lungs. The trough is 
made of vulcanite, and is watertight, but at the posterior end is a 
sliding piece by which that end can be opened and a thread passed 
through to the lever of a myograph. In convenient situations are 
binding screws for the connection of wires from a coil or battery. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 625 


Hither or both of the projecting portions of the trough can be shut off 
from the main receptacle by sliding hatches (not shown in the fig.) 
if necessary, and the part containing the body of the frog can be 
covered with glass or a vulcanite lid. Should it be desired to observe 
the effect of gases or of heat or cold, the required gases or warm 
or cool air may be conducted through the body chamber by means 
of the two small tubes seen projecting from the front and sides 
respectively. 

The frog to be observed is placed either ventrally or dorsally as 
may be required, and is held by means of loops of thread passed 
round the arms and then led through screw-eyes and clamped up. 
The thighs are held by a pair of stocks, which, by means of a sliding 
upper half, can be adjusted accurately to the limbs without causing 
constriction ; and the webs are spread out by pinning loops of thread 
tied to the toes. 


Visibility of Ruled Lines.*—C. Fasoldt writes, in regard to the 
-note by Professor W. A. Rogers, which appears at p. 489 of vol. iii. 
(1883), that “there are some statements which do not agree with my 
experience. I find that lines properly ruled on glass are similar to 
graven lines; they are smooth, clean cut, having a definite shape and 
depth. Such lines are always visible in the Microscope, and central 
or oblique light will show the bottom of each cut as a dark or 
coloured line, plainly visible, and requiring no graphite or other 
foreign substance to indicate it. The Microscope is the test for a 
properly ruled line. The mechanical elements (pressure, &c.) enter- 
ing into the process of ruling are not at all evidences that lines have 
been properly ruled. The slightest accident to the point of the 
cutter, or the surface of the glass not being perfectly clean, will spoil 
a line; that is, produce a scratch which cannot be satisfactorily 
illuminated in any light. Well-ruled bands of lines, 70,000 or 
80,000 to the inch, are visible in the Microscope with central light ; 
and with a Smith vertical illuminator (giving central light), I have 
seen 100,000 lines to the inch. As these individual lines have a 
width of about 1/200,000 of an inch only, it follows that the difficulty 
is not to see such a narrow line, but to eliminate the diffractions 
which tend to blur the image in the Microscope, and so prevent the 
resolution or separation of the lines in a band of them.” 


Mercer’s Photomicrographic Camera.t-——Dr. F. W. Mercer has 
devised the camera shown in fig. 106. It consists of a box of light 
wood A, a cone of light metal B, a tube which takes the place of the 
ordinary draw-tube of the Microscope, C, and the frame carrying the 
ground glass and plate-holder, D. The tube C is fitted to the cone 
B, so that it may be withdrawn for the insertion of an eye-piece or 
amplifier. To the box A is attached a brass strap a, the lower end 
being slotted to admit the passage of a binding screw secured to a 
button b, fastened to the arm of the stand. As soon as the object 
is coarsely focused upon the ground glass the cone and its tube are 


* Scientific American, xlviii. (1883) p, 341. 
¢ ‘ Photography’ (Chicago), i. (1884) pp. 9-10 (1 fig.). 


626 SUMMARY OF CURRENT RESEARCHES RELATING TO 


raised slightly, say about a quarter of an inch from the body of the 
Microscope, and the binding screw is then tightened, securing the 
weight of the camera, &c., upon the arm of the instrument, thus 
removing any undue pressure upon the rack and pinion, or fine move- 
ment of the tube, during future manipulation. The fine focusing 


Fic. 106. 


when completed leaves nothing to be done but to push the ground- 
glass frame on till it is replaced by the plate-holder, when the picture 
may be made. 

The features claimed for this apparatus are: “Its great porta- 
bility, measuring when the draw-tube has been removed from the 
cone, 44 x 41 x 9 in.; its ready application to the Microscope 
in any position from the vertical to the horizontal, requiring but a 
few minutes for its adjustment without changing the position or light, 
at least for moderate powers; its special fitness for the amateur, being 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 627 


moderate in first cost and inexpensive in use from the size of the 
plate used. Though the plate is small, 3} x 4 in. (lantern size), it 
is very useful and will meet most of the needs of the amateur workers 
for whose convenience the instrument is intended. 

There is a class of work of which this little camera is incapable, 
and in introducing it to the notice of microscopists, it is not intended 
to convey the impression that it will supersede other means where 
skilled hands and elaborate apparatus are absolutely necessary. To 
those who have but an hour or two of an evening for observation with 
the Microscope, this camera may prove of service in securing a photo- 
graph quickly at the work-table. 

The box above the cone might be dispensed with, and the slide 
carrying the ground glass attached directly to the large end of the 
cone. The advantage in having the box is the shutter, which may be 
fitted to its interior for excluding light from the plate at the moment 
of completing the exposure, a preferable means to that of placing a 
piece of black paper between the objective and the source of light. 
Instead of having the ground glass and plate-carrier in one frame, it 
might be desirable for some to have them separate, having more than 
one plate-holder. The apparatus can at a trifling cost be attached to 
most stands, and when properly made should not exceed, including 
ground glass and plate-holder, seven or eight ounces in weight.” 


Photographing Bacillus tuberculosis.*—M. Defrenne describes 
the process which he adopts to photograph this Bacillus with a Tolles’ 
1/10 in. (hom. imm.), without eye-piece, using extra rapid bromo- 
gelatine plates, developed with ferro-oxalate, a petroleum lamp being 
employed for illumination. 

If, he says, the determination of the actinic focus of objectives 
constitutes, so to say, the chief difficulty in photographing ordinary 
microscopic preparations, it is no longer so when we deal with 
organisms so infinitesimally small as the bacilli of tuberculosis. 
Here arises a difficulty of quite another kind, which at first seemed 
insurmountable: the staining of the bacilli by means of fuchsin. 
This agent, even when it is employed in thick layers, is somewhat 
actinic, and it becomes the more so as the object stained is smaller or 
more transparent. These two circumstances are combined in the highest 
degree in the organisms in question. Thus at the beginning the 
plates exposed were either uniformly acted on or the image was so 
faint and so little differentiated after development that they were 
worthless for proofs on glass or on paper. 

These negative results suggested the abandonment of the attempt, 
when the idea was suggested of having recourse to the use of a com- 
pensating glass of a colour complementary to red (that is green), placed — 
between the objective and the sensitized plate. By thus filtering the 
image formed by the objective, the red rays, the only ones passing 
through the bacilli, are absorbed, if not wholly, at least in great part. 
The microbes therefore appear nearly black on the plate, and make 


* Bull. Soc. Belg. Mier, x, (1884) pp, 128-32. 


628 SUMMARY OF CURRENT RESEARCHES RELATING TO 


a much slower impression than the rest of the preparation, which 
gives free passage to all the green rays. More contrast is thus 
obtained and a very distinct photograph produced. 


Beck’s ‘‘Complete ’’ Lamp.—For pathological and physiological 
investigation, as also for many other branches of microscopical 


Fia. 107. 


1 


| 
if 


| 

i 
i 
| 

i 
Hi 


i 
| 
i 

| 

i 
| 
| 


Sart 


Samet oe ma, 


ole 


ole 


a 


research, a lamp more delicate in its adjustments and giving a 
greater control over the light than those ordinarily in use is requisite, 
and Messrs. Beck have therefore constructed a lamp whereby more 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 629 


perfect illumination of both opaque and transparent objects can be 
obtained. 

The base A (fig. 107) consists of a heavy ring, into which a square 
brass rod B is screwed. The square rod carries a socket C with an 
arm D, to which the lamp is attached. This socket fits the square 
rod loosely, but is kept in any position by a lever HE, which is 
pressed firmly against the square rod by a strong spring. If the 
lever and the opposite side of the socket are taken between the 
thumb and finger, the pressure of the lever on the bar is removed, 
and the lamp can be raised or lowered to the desired position, when 
by releasing the hold the lamp is at once clamped. 

On each side of the burner, and attached to the arm D, is an up- 
right rod G, to one of which the chimney is fixed, independent of the 
reservoir of the lamp, but fitting closely over the burner, thus 
enabling the observer to revolve the burner and reservoir, and obtain 
either a thin intense light or a broad and diffused one, without alter- 
ing the position of the chimney. The chimney F is made of thin 
brass, with two openings opposite to each other, into which slide 
3 x1 glass slips of either white, blue, or opal glass, the latter serving 
as a reflector. 

The reservoir, although holding enough oil to burn for several 
hours, is made very flat, and drops into the annular base, thereby 
bringing the flame of the lamp within 3 inches of the table, render- 
ing it much more serviceable for direct illumination (without the 
mirror) and for other purposes. 

A semicircle swings from the two uprights G, to which it is 
attached by the pins H, placed level with the middle of the flame ; 
to this semicircle is fixed a dovetailed bar L, carrying a sliding 
fitting O, which bears a Herschel condenser P. 

This condenser, swinging with the middle of the flame as a centre, 
is always at the same distance from it; and thus, when once focused, 
needs no further alteration for any change in the inclination of the 
beam of light. The condenser is fixed at any inclination by a milled 
head working in a slotted piece of brass K, fixed to the arm D. 

When used for transparent illumination, the condenser is not 
required below the horizontal position ; but when the lamp is re- 
quired for the illumination of opaque objects, the chimney having 
been temporarily removed and the milled head fixing the condenser 
arm having been loosened, the arm with the condenser can be thrown 
over the lamp, as shown in the illustration at M, and the chimney 
being replaced, the light, which now comes through the opposite 
opening of the chimney, can be condensed at a large angle below the 
horizontal. 

James’ ‘ Aids to Practical Physiology. *—It is beyond our com- 
prehension how this extraordinary book could ever have been written 
by an author entitled to add M.R.C.S. to bis name, or published as a 
volume of ‘Students’ Aids Series’ by such publishers as those whose 


* J. Brindley James, M.R.C.S., ‘ Aids to Practical Physiology,’ 8vo, London 
(Bailliere, Tindall, & Cox), 1884, viii. and 60 pp. 


630 SUMMARY OF CURRENT RESEARCHES RELATING TO 


names are attached to the title-page, which moreover bears the motto 

‘Mens sana in corpore sano.” That we do not criticize it without 

reason will be seen by the following extract which is prefaced by the 

statement that it contains a “few practical hints which we trust may 

“powerfully tend to facilitate the young experimentalist’s labours.” 
The italics are ours.) 

“The Microscrope (sic).—You cannot expect to get one of any 
valuable power (!) under five guineas. It should be of two powers, 
enabling you to use inch and quarter-inch glasses(!) The hole in 
the stage should have its awis diametrically consistent (!) with that of 
the tube of the instrument. A stand is also needed (!!) Object-glasses, 
denoted as one-fourth, one-fifth, one-sixth, are used for high powers, 
one-half to two-fifths (!) for low. An oil-immersion lens is now-a-days 
a necessary complement, and should be about one-twelfth. The 
simpler it is the better for a beginner(!) The same may be said of 
the eye-piece (!!) With respect to such other adjuncts as achromatic 
condensers, special stands, &c., these concern the accomplished micro- 
scopist rather than the tyro.” 

As it was obvious that the author was not at home in the optical 
branch of his subject, we turned to the description of a piece of 
apparatus with which the practical physiologist should necessarily be 
intimately acquainted—the Microtome. Will it be believed that it is 
described not as an instrument for cutting sections, but for freezing 
specimens! The author’s own words are as follows: “'The Micro- 
“tome. This useful device for freezing specimens is susceptible of 
“ various forms of construction.” 

After these extracts it is superfluous to refer to the other minor 
blunders which disfigure the book, such as the description of Dr. Klein 
as “Klean,” the indiscriminate use of “bichromate of potash,” 


“ pnotass ” and “ potassium,” and “ potassic bichromate” for the same 
p 2 
substance. 


Postal Microscopical Society.—This society is now forming a 


section specially devoted to members of the medical profession (in- 
cluding students). 


“A PRESIDENT.”—Suggestion for making the ‘ Journal of Microscopy’ the Journal 
of provincial and other Microscopical Societies. 


Journ. of Micr., III. (1884) pp. 194-5. 
‘* AMATEUR.”’— Bacteria and the Microscope. 


[Elementary Inquiries. | Engl. Mech., XXX1X. (1884) pp. 465-6. 
American Society of Microscopists, Session of 1884.—Circulars of President 
J. D. Cox, and E. H. Griffith. - Micr, Bull., 1. (1884) pp. 25 and 28. 


Amer, Mon. Micr. Journ., VY. (1884) pp. 117-8. 
The Microscope, IY. (1884) p. 133. 
BELFIELD, W. T.—Photo-micrography in Legal Cases. [ Post. ] 
Photography (Chicago); I. (1884) pp. 54-9 (7 figs.). 
Brappury, W.—Papers relative to the theory of the Object-glass. 

[Note introducing paper by Dr. C. S. Hastings, from ‘ Amer. Journ. Sci.,’ 
detailing the method used by him to determine the optical properties of 
various kinds of glass and the alterations in the properties when the 
glass was subjected to different temperatures. ] 

Engl. Mech., KXXIX. (1884) pp. 420-1. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 631 


Butiocu, W. H.—The Congress Nose-piece. 

(Further rejoinder to Prof. McCalla’s claim of priority. } 

Amer. Mon. Micr. Journ., V. (1884) pp. 119-20. 

Carnoy, J. B.—La Biologie Cellulaire. Etude comparée de la cellule dans les deux 

Régnes. (Cellular Biology; a comparative study of the cell in the two 
kingdoms.) Fase. I. 271 pp. and 141 figs. 8vo, Lierre, 1884. 

[Part I. Microscopical Technics (pp. 37-167, 24 figs.). 1. On instruments 
and the laboratory of the microscopist or cytologist. 2. On objects and 
their preparation. 3. On the method to be followed in microscopical 
observations and cytological researches. ] 

CARPENTER, W. B.—Article “Microscope” in the ‘Encyclopsdia Britannica,’ 
9th ed., XVI. 4to, Edinburgh, 1883. [Cf ante, pp. 448 and 620.] 
Cox, J. D.—See American. 
sx Photographs showing the structure of Diatom shells. 
Amer. Mon. Mier. Journ., V. (1884) p. 112. 
D., E. T.—Graphie Microscopy. VI. Pupaof Locust, oneday old. VII. Cluster 
Cups: Zcidium quadrifidum. 
Sci.- Gossip, 1884, pp. 121-2 (1 pl.), 145-6 (1 pl.). 
DEFRENNE.—Présentation d’une Microphotographie du Bacillus tuberculosis. 
(Exhibition of a photomicrograph of Bacillus tuberculosis.) With remarks by 
E. yan Ermengem. ([Supra, p. 627. ] 
Bull. Soc. Belg. Micr., X. (1884) pp. 128-32. 
Dun ey, Prof.—Microscopic Photography: 
[Response to a toast. ] Photography (Chicago), I. (1884) pp. 71-2. 
Ermencem, E.—See Defrenne. 
F.R.A.S.—Optical Recreations. 
(Containing a note on the convex lens used as a magnifying glass. | 
Knowledge, VI. (1884) pp. 46-7 (4 figs.). 
Francotre, P.—Aspirateurs pour tenir constamment saturee d’air l’eau des 
récipients ot l’on observe les animaux et les plantes aquatiques. (Aspirators 
for keeping saturated with air the water of receptacles for observing aquatic 


animals and plants.) (Post. ] Bull. Soc. Belg. Micr., X. (1884) pp. 141-3. 
Giant Electric Microscope. 
[Criticism of its defects.] Journ. of Sci., VI. (1884) p. 370. 


Git, D.— Article “ Micrometer” in ‘ Encyclopedia Britannica,’ 9th ed., XVL., 
p-. 248. 4to, Edinburgh, 1883. 
[Contains “ How to web a filar micrometer.” Post.] 
Gowen, F. H.—Resolution of Amphipleura. 

[Direct sunlight above the stage. ‘The Microscope should be so placed 
that the light may fall on the circumference of the stratum of immersion 
fluid obliquely to the upper surface of the slide, and care should be 
taken to have one end of the frustule point towards the sun.” 

Amer. Mon. Mier. Journ., V. (1884) p. 118. 
iy ef Resolution by Central Light. 

(Resolution of A. pellucida in balsam by sunlight with the mirror in a strictly 
central position. ‘The resolution was effected by light reflected within 
the slide from one of its convex edges, and that instead of being central 
the light was very oblique.” ] 

Amer. Mon. Micr. Journ., V. (1884) pp. 118-9. 
Grirrits, E. H—See American. 
Harpy, J. D.—Microscopical drawing. 
[Report of demonstration.]} Journ. Quek, Micr, Club, I. (1884) pp. 360-1. 
Hastines, C. 8.—See Bradbury, W. : 
Haziewoop, F. T.—A home-made revolving table. 

[‘‘I got a second-hand sewing-machine table . . . Then I took another 
table-top which was raised about 2 in. from the other by a moulding. 
On the top of the first table I put a piece of pine board 1 in. thick. Into 
this I put three small castors upside down. I bored three holes in the 
top of the other table, on radii, from acommon centre. Then I put top 
No. 2 over top No. 1, 80 that the castors came over the surface about 1/4 in. 


632 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Through the centre of both tables I bored another hole. Then I took 
a steel saw-plate into which the teeth had not been cut. I hada hole 
bored in its centre, and two brass handles or pins put in opposite each 
other near the circumference. This plate is fastened by a pin with nuts 
on the table over the three castors. The table is perfect. I painted the 
steel plate. The drawer of the first table on the side serves for accessories. 
The whole thing cost less than five dollars. The finished table looks as 
though made for this purpose, and not for a sewing-machine.”’] 

Amer, Mon. Micr. Journ., V. (1884) p. 94. 


Herricz, S. B—The Wonders of Plant Life under the Microscope. 248 pp. and 
85 figs. 8vo, London, 1884. 


Hertwic, O.— Die Verwendung des Sciopticons als eines Anatomischen 
Unterrichtsmittels. (The employment of the Sciopticon for anatomical 
instruction.) 

[Exhibition of glass photograms and sections. ] 
SB. Jenaisch. Gesell. Med. § Naturwiss., 1883, p. 17. 


Hevurcs, H. Van—[Protest against the review of his ‘‘ Lumiere électrique,” by 
Stein, in ‘ Zeitschr. f. Wiss. Mikr.’] 
Journ. de Microgr., VIII. (1884) pp. 273-7. 
Hircucocn, R.—The Postal Microscopical Club. 
[Exhortation to put better slides in the boxes. ] 
Amer. Mon. Micr. Journ., V. (1884) pp. 113-4. 
James, F. L.—The St. Louis Microscopical Society. 
| Notification of its formation. ] The Microscope, 1V. (1884) pp. 129-30. 
James, J. B.—Aids to Practical Physiology. viii. and 60 pp. 8vo, London, 1884. 
[ Supra, p. 629.] 
Liguton, W.—Immersion Illuminator. [Supra, p. 621.] 
Amer. Mon. Micr. Journ., V. (1884) pp. 102-3 (1 fig.). 
Mosivus, K.—Rathschlage fiir den Bau und die innere Hinrichtung zoologischer 
Museen. (Advice on the construction and internal arrangement of Zoological 
Museums.) 
[Contains a reference to the ‘‘ Microscopirzimmer. ” 
Zool. Anzeig., VII. (1884) pp. 378-83. 


Mu uer, P.—Insectenfanger mit Lupe. (Insect-catcher with lens. Post.) 
German Patent No. 25,806, 6th June, 1883. See 
Zeitschr, f. Instrumentenk., IV. (1884) pp. 259 (1 fig.). 


Neson, E. M.—How to Work with the Microscope. 

[Report of demonstration. See ante, pp. 447 and 464. The view originally 
expressed as to the decided preference to be given to the Ross form over 
the Jackson is modified. “In point of steadiness he did not think there 
was much to choose between them in first-class stands.” 

Journ. Quek. Micr. Club, I. (1884) pp. 375-9. 
5 * The Health Exhibition. \ 

[Description of Microscopes, Apparatus, &c., exhibited. ] 

Engl. Mech., XX XIX. (1884) pp. 437-9. 
Rogers, W. A.—On a practical solution of the perfect screw problem. 

[Describes the method by which it is claimed a perfect screw can be made 
on a commen lathe, including a Microscope provided with Tolles’ opaque 
illuminator attached to the carriage moved by the leading screw of the 


lathe. ] 
Engl. Mech., XX XIX. (1884) pp. 341-2. 


Royal Microscopical Society: Notes as to the admission of ladies and rearrange- 
ment of the Cabinet. Journ. of Sci., VI. (1884) p. 437. 


ScHNEIDER, E.—Ueber eine Justirvorrichtung an einem Krystallgoniometer. 
(On an adjusting arrangement for a Crystal Goniometer.) 
[Differential screw. ] 
Zeitschr. f. Instrumentenk., TV. (1884) pp. 242-4 (1 fig.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 633 


Ster, 8. T.—Das Mikroskop und die mikrographische Technik zum Zwecke 
photographischer Darstellung. (The Microscope and Microscopical Technie 
in Photographic representation.) Part II. of ‘Das Licht im Dienste 
wissenschaftlicher Forschung,’ 2nd ed., pp. i—ix. and 151-822, figs. 168-302, 
pls. iili-vi. S8vo, Halle a. 8., 1884. 


Srowe.i, C. H.—Rochester meeting [of American Society of Microscopists]. 
The Microscope, IV, (1884) pp. 131-2. 
SrrasBuRGER, E.—Das botanische Practicum. Anleitung zum Selbststudium der 
mikroskopischen Botanik fiir Anfanger und Fortgeschrittnen. (Practical 
Botany. Guide to the study of microscopical Botany for beginners and 
advanced students.) xxxvi. and 664 pp., and 182 figs. 8vo, Jena, 1884. 


TatsoT, R.—Das Scioptikon, Vervollkommneter Projectionsapparat fiir den 
Unterricht. 7th ed., vi. and 82 pp. 8vo, Berlin, 1884. 
[Mainly a Catalogue of Photograms and microscopical preparations. ] 
Tuurston, E.—The Microscope : its Construction and Manipulation. 
Micr. News, 1V. (1884) pp. 150-2. 
Waters, W. H.—Histological Notes for the use of Medical Students. vi. and 
65 pp. 8vo, Manchester and London, 1884. 


(‘The body-tube of the Microscope is (not aptly) styled the “ telescope-tube ”’ ! 

and the concave mirror the “ curved mirror.” ] 
Wenham Button. 

(To keep the Wenham button or the common hemispherical lens in position 
while examining temporary mounts, fix it with glycerin or immersion 
fluid to that surface of a slide on which has been turned a wax or an 
asphalt ring, the internal diameter of which corresponds to the diameter 
of the lens. Invert the slide, and it is ready for use. 

The Microscope, TV. (1884) p. 134. 


8. Collecting, Mounting and Examining Objects, &c. 


Methods of Investigating Animal Cells.*—Dr. A. Brass has de- 
voted several years of close study to the structure and life of animal 
cells, and gives a detailed account of his methods. The following 
are some of the more important of these methods :— 

1. Protozoa.—As most Protozoa move very rapidly when hungry, 
it is well to feed them before attempting to study them with the 
Microscope. If well fed with powdered pieces of plants, &c., they 
usually remain quiet after a short time, and begin to assimilate the 
food-material which they have appropriated. In this condition of 
comparative quiet they can be easily examined with high powers. 
For this purpose they may be placed under a cover-glass with a 
considerable quantity of water and a number of small green alge to 
keep the water supplied with oxygen. 

For higher powers Abbe’s illuminating apparatus is extremely 
useful. In some cases it is desirable to have a completely one-sided 
illumination, and this is best effected by inserting beneath the 
illuminating apparatus a circular diaphragm-plate perforated with 
a slit 2 mm. wide that runs parallel to the edge of the plate. It 
is best to leave about 2 mm. between the slit and the edge of the 


* Zeitschr. f. Wiss. Mikr., i, (1884) pp. 39-51, Cf, Amer. Natural., xviii. 
(1884) pp. 650-1. 


Ser. 2,—Vo1. LY. ov 


634 SUMMARY OF OURRENT RESEARCHES RELATING TO 


plate. Several diaphragm-plates should be prepared in which the 
slit varies in extent from a half to a whole of a quadrant or more. 

The following mixture, which is Meckel’s fluid with the addition 
of a little acetic acid, is recommended above all other reagents as a 
preservative medium : 


@hromiciacid ois 4 ee) ie ee eee ge eee panty 
Platinum ehloridey auc) iscsi alesse ae een 
Acetic acid He eS. poh raeion Rah hmhacne MARR a hla pa 
Water 94% fn a 400=1000 parts: 


Unicellular animals die very slowly in this mixture, and suffer 
very much less alteration in structure than when killed in osmie acid 
or picro-sulphuric acid. 

A special method is required for Protozoa filled with opaque food- 
material. In many cases the nucleus and the structure of the cell- 
body are completely obscured by foreign bodies. The method 
adopted in such cases is as follows :— 

(1) Placed in picro-sulphuric acid 3-4 minutes. 

(2) Transferred to boiling hot water for a short time. 

(3) Placed in water and a little ammonia added; this causes the 
contracted object to swell up to its original size and form. 

(4) Neutralize the ammonia with a little acetic acid, and then 

5) Colour with borax-carmine or ammonia-carmine. 

(6) Wash and examine in dilute glycerin. 

The picro-sulphuric acid destroys the nutritive material; the 
ammonia dissolves any particles of fat that may be present; and thus 
the object becomes transparent as far as. possible. 

A concentrated solution of corrosive sublimate may also be used 
with success for killing Protozoa; but care must be taken to wash 
thoroughly. 

Dr. Brass has obtained his best results without reagents or dyes. 


Born’s Method of Reconstructing Objects from Microscopic 
Sections.*—Dr. G. Born describes in detail a very ingenious method 
of constructing models of objects from serial sections. By the aid of 
the camera the outlines of the sections are transferred to wax plates, 
which are then cut out so as to correspond in outlines as well as 
dimensions to the sections equally magnified in all three directions. 
With plates thus prepared, it is only necessary to put them together 
in the proper order to obtain a complete model. The method is 
simple and extremely useful, especially in investigating objects with 
complex internal cavities. Born has made use of the method in 
studying different parts of the vertebrate head; Swirski, in eluci- 
dating the development of the shoulder-girdle of the pike; Stohr, in 
tracing the development of the skull of Amphibia and Teleostei; and 
Uskow, in studying the development of the body-cavity, the 
diaphragm, &e. 


* Arch. f. Mikr. Anat., xxii. (1883) pp. 584-99. Cf. Science, ii. (1883),p. 802, 
and Amer. Natural., xviii. (1884) pp. 446-8. 5 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 635 


Born makes use of three rectangular tin boxes of equal sizes, each 
measuring 270 mm. x 230 mm. x 24 mm. Sections should be made 
about 1/25 mm. thick (never thinner than 1/50 mm.). If we desire 
to construct a model of an object from serial sections 1/30 mm. thick, 
which shall be magnified 60 diameters, then the wax plates must be 
made 60 times as thick as the sections, i.e. 2 mm. thick. 

The surface of a plate that could be made in a box of the above- 
named dimensions, contains 62,100 sq. mm.; and the volume of such 
a plate 2 mm. thick would therefore be 124°2 c.cm. The specific 
gravity of common raw beeswax amounts to ‘96-97. For use, it 
requires only to be melted ‘and a little turpentine added to make it 
more flexible. Thus prepared, its specific gravity is about *95; and 
this number has been found sufficiently accurate in all cases. The 
weight of the wax required to make one plate of the above size, will 
accordingly be 117°99 gr., or, in round numbers, 118 gr. The wax 
having been weighed and melted, the tin box is first filled 14 cm. 
deep with boiling water, and then the melted wax poured upon the 
water. If the water and the wax are quite hot, the wax will gene- 
rally spread evenly over the surface; if gaps remain, they can be 
filled out by the aid of a glass slide drawn over the wax. As soon as 
the plate has stiffened, and while it is still soft, it is well to cut it 
free from the walls of the tin box, as further cooling of the water and 
the box might cause it to split. By the time the water becomes 
tepid, the plate can be removed from the water to some flat support, 
and left till completely stiffened. Half a hundred plates may thus be 
prepared in the course of a few hours. 

The outlines of the section are transferred to the plate in the 
following manner: a piece of blue paper is placed on the plate with 
the blue side turned towards the wax, and above this is placed a sheet 
of ordinary drawing paper. The outlines are drawn on the latter by 
the aid of a camera, and at the same time blue outlines are traced on 
the wax plate. The plate can then be laid on soft wood and cut out 
by the aid of a small knife. Thus a drawing and a model of each 
section are prepared. The plates thus prepared can be put together 
in the proper order, and fastened by the aid of a hot spatula applied 
to the edges. 


Shrinking Back of Legs of Oribatide in Mounting.*—A. D. 
Michael suggests a mode of getting over the difficulty of the shrinking 
back, during the process of mounting, of the legs of species of Oribata 
and other genera which have special cavities for the reception of the 
legs. The process requires careful manipulation, but if well done is 
very successful. Place a very thin layer of balsam upon the slide 
upon which the specimen is to be soaked in oil of cloves; when this 
layer becomes sticky the specimen is placed upon it, dorsal surface 
downwards. The mounter must then extend the legs and stick them 
to the balsam, if they rise up they should be pressed down again with 
a hair; when they are all fast the body should be brushed over with 
the smallest possible quantity of oil of cloves to prevent its drying, 


* «British Oribatidw’ (Ray Society) 1884, pp, 104-5. 
20 


636 SUMMARY OF CURRENT RESEARCHES RELATING TO 


but without touching the legs. This brushing with oil of cloves must 
be repeated from time to time as it sinks into the body. Whena 
creature is ready, which can only be learned by experience, a large 
drop of oil of cloves, not benzole, may be put on; when this has 
thoroughly dissolved the balsam, but not before, the specimen may be 
moved and mounted, or further soaked in oil of cloves. 


Preparing the Liver of the Crustacea.*—For the study of fresh 
tissues J. Frenzel places a small piece of the organ on the slide, in 
the blood of the individual from which it was taken ; or, in sea-water 
diluted until the salt contained amounts to about 13-2 per cent. (one 
part distilled water and one part sea-water from the Bay of Naples). 
The so-called “ physiological salt-solution” (8/4 per cent.) worked 
unfavourably, causing maceration. 

Various fluids were employed for killing and hardening, partly 
for determining the effect of different reagents on the nuclei and 
the protoplasm, and partly for finding the best means of preparing 
the object for sectioning. 

Very good preparations were obtained with warm alcohol from 
70-90 per cent.; while direct immersion in absolute aleohol did not 
prove advantageous. This treatment gave good results for the cell- 
protoplasm, but destroyed the structure of the nuclei, Still better 
results were obtained for the cells (not for the nuclei) by adding a 
few drops of iodine to 70 per cent. alcohol. 

The most satisfactory results were reached by immersing the 
object in a saturated aqueous solution of corrosive sublimate from 
ten to thirty minutes, then washing with water, and finally replacing 
the water gradually with alcohol. 

Perenyi’s fluid gave best results when combined with corrosive 
sublimate. The object was left from five to ten minutes in the 
first-named fluid, then transferred to the second and left for the same 
time. 

While these methods were good for the Decapods, Amphipods, and 
Phronimide, the Isopods required a different treatment. With these, 
Kleinenberg’s picro-sulphuric acid, diluted with an equal volume of 
water, and allowed to act 15-20 minutes, gave much better preparations 
than the sublimate solution. 


Preparing Alcyonaria.{—In studying the mesenterial filaments 
of the Alcyonaria, E. B. Wilson obtained the best results in the 
following manner. 

The animals were suddenly killed by momentary immersion in a 
mixture of 1 part strong acetic acid and 2 parts of a concentrated 
solution of corrosive sublimate in fresh water. After being quickly 
washed, they were transferred to a concentrated solution of sublimate 
in fresh water and left two or three hours; the internal cavities 
being injected with the solution, where this was possible. The 
were then thoroughly washed in running sea-water, then in distilled 


ees Zool, Stat. Neapel, v. (1884) p. 51. Amer. Natural., xviii. (1884) 
pp. 556-7. 
+ MT. Zool. Stat. Neapel, v. (1884) p. 3. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 637 


water, and finally preserved in successive grades of alcohol. A 
weak solution of iodine in alcohol and sea-water also gives beau- 
tiful results, but is less certain in its action. For staining he 
used Grenacher’s alum-carmine, borax-carmine, picro-carmine, and 
Kleinenberg’s hematoxylin. Much the best results are obtained by 
the use of alum-carmine, but it must be used as quickly as possible, 
since the gelatinous tissue of the mesoderm is apt to shrink if the 
object be left too long in aqueous fluid. The tissues were decalcified 
with very weak nitric or hydrochloric acid in 90 per cent. alcohol. 
For maceration, the Hertwigs’ well-known mixture of osmic and 
acetic acid gives good results. 


Semper’s Method of making Dried Preparations.*—B. Sharp 
redescribes this process. 

After hardening in chromic acid solution (4-1 per cent.) and being 
repeatedly washed, the object is placed in alcohol, 30-40, 60-70, and 
90-95 per cent. successively, and finally in absolute alcohol. 

This stage of absolute alcohol is the most critical part of the 
whole process. Absolutely every particle of the water must be removed, 
and the secret of the whole process depends on this one point. If 
any water be left in the tissue, it will become spotted and eventually 
spoil. After all the water has been withdrawn by the absolute 
alcohol, by remaining in it for three days to a week, the object is 
placed in turpentine, the best that can be procured. In this it is 
allowed to remain until it becomes thoroughly saturated: with large 
objects it is best to change the turpentine once. Two or three days 
are required for this stage. When saturated, the object is quite stiff, 
and when the process is successful little or no contraction has taken 
place. The object is then placed in the air and protected carefully 
from the dust, and the turpentine allowed to evaporate. The object 
then soon presents a very beautiful appearance; it becomes white, 
resembling the whitest kid. It is light, stiff, and, on account of the 
resin it contains, is perfectly insect-proof. In annelids the iridescence 
is perfectly kept ; hair and feather retain their original colours. 


Method of Detecting the Continuity of Protoplasm in Vegetable 
Structures.{—W. Gardiner makes the following observations on the 
various methods for observing the protoplasmic threads which pass 
from cell to cell. 

During the earlier part of his work he used sulphuric acid in 
combination with Hoffmann’s violet. This latter reagent, at the 
time of staining, colours equally protoplasm and cell-wall. If, 
however, the section be treated for some time with dilute glycerin, 
the staining of the cell-wall is removed, and the protoplasm alone 
remains clearly stained. A very useful reagent for the demonstration 
of sieve-tubes may be made by dissolving Hoffmann’s violet in strong 
sulphuric acid. After treatment with this solution the sieve-tubes 
are well brought into view, and all lignified tissue assumes the usual 


* Proc. Acad. Nat. Sci. Philad., 1884, pp. 24-7. 
+ See this Journal, i. (1881) p. 706. 
t Arbeit. Bot. Inst. Wiirzburg, iii. (1884) pp. 53-60 (English). 


638 SUMMARY OF CURRENT RESEARCHES RELATING TO 


gold-yellow tint, as after treatment with aniline chloride and hydro- 
chloric acid. 

In working with sulphuric acid the fresh material is first cut 
in water. A section having been taken up with a platinum spatula, 
-and the excess of water removed by blotting-paper, a drop of strong 
sulphuric acid is placed upon it, and allowed to act for a short 
time, usually a few seconds. The section is then plunged into water 
and rapidly washed. After several washings it may be stained and 
mounted. Asa staining reagent, either Hoffmann’s violet or prefer- 
ably Hoffmann’s blue may be used. In the former case the section 
is quickly stained, washed in water, and then placed for twenty-four 
hours or more in dilute glycerin, which dissolves out a great portion 
of the dye from the stained cell-wall, and at the same time removes 
the peculiar staining of the pits, which, if allowed to remain, is apt 
to lead to very delusive results. The section is finally mounted in 
glycerin. When Hoffmann’s blue is used, a moderate quantity of 
the dye is dissolved in a 50 per cent. solution of alcohol to which 
have been added a few drops of acetic acid. After staining, the 
sections are washed with water and mounted in glycerin. Or a suffi- 
cient quantity of the dye may be dissolved in a 50 per cent. solution 
of alcohol which has been saturated with picric acid, until the solution 
assumes a dark greenish-blue tint. To this solution Gardiner gives 
the name picric-Hoffmann’s-blue. After staining, the sections are 
washed with water and mounted in glycerin as before; or, after treat- 
ment with alcohol, they may be cleared with oil of cloves and mounted 
in Canada balsam. 

In Tangl’s method, sections of endosperm were stained with iodine 
and mounted in chlor-zinc-iod. In such dry tissue as ripe endo- 
sperm cells the cell-walls do not turn blue, but merely remain stained 
with the ordinary yellow-brown due to iodine. The protoplasm, on 
the other hand, assumes a very dark brown coloration, and after 
some time there comes into view a series of strie traversing the 
thickened cell-wall, which, from their coloration, and from the 
fact that their depth of staining varies pari passu with that of the 
protoplasm, are taken to be essentially protoplasmic in character. 
Although in cases where it can be applied this method is of great 
value, it is attended also with some disadvantages. Firstly, in tissues 
containing a higher percentage of water the walls assume the ordinary 
cellulose blue, which at once prevents the threads from being seen ; 
and, secondly, on account of the extensive and varied staining pro- 
perties of the iodine, the results obtained by it alone cannot be taken 
as entirely conclusive. But, where practicable, Tangl’s method is 
of great use in giving at least an idea of the existence of the proto- 
plasmic threads, and the staining of the threads with iodine is much 
more distinct than with any other reagent. 

To obviate these difficulties Gardiner adopted the modification 
already described of dissolving Hoffmann’s blue in a 50 per cent. 
solution of alcohol saturated with picric acid ; and, on washing out, 
the threads were found to be well stained, the picric acid bodily 
carrying, as it were, the solution of the dye into the fine protoplasmic 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 639 


strands. Picric acid has also another valuable property in tending to 
prevent the staining of cellulose by dyes which, although possessing 
an especial affinity for protoplasm, will stain the cell-wall also unless 
some such restraining reagent be used. The sections are first stained 
with iodine and mounted in chlor-zinc-iod. If the material is 
favourable, something may then be seen of the threads. After being 
exposed to the action of the chlor-zinc-iod for about 12 hours, 
the sections are well washed, stained with picric-Hoffmann’s-blue, 
washed again in water, and finally mounted in glycerin, or, better still, 
placed in alcohol, first dilute and at length absolute, cleared with oil of 
cloves, and mounted in Canada balsam. In those cases where the tissue 
swells rapidly under the action of the reagent, as in the endosperm of 
Strychnos nux-vomica, Bauhinia, and Tamus, the action need not be so 
prolonged, and the excessive swelling must be prevented by the use of 
alcoholic iodine at the outset, and in a similar manner it may be 
washed with alcohol instead of with water, otherwise the threads will 
be so displaced or altered as to be almost or entirely invisible. 

As regards the management of the reagents, and the length of time 
they must be allowed to act to obtain a satisfactory result, the mani- 
pulation must be varied to a certain extent to suit the requirements of 
the various kinds of tissue, according as it is thick- or thin-walled, 
easily swollen or only with difficulty. The use of sulphuric acid is 
attended with a much greater amount of difficulty; for if it is 
allowed to act for too short a time, the cell-wall will not be sufficiently 
swollen; while if the treatment is prolonged, the middle lamelle of 
the walls are liable to swell and at the same time stain, and will 
then hinder all successful observation of the threads which may traverse 
their substance. Upon still further action the protoplasm itself com- 
mences to be attacked. With chlor-zinc-iod, on the other hand, 
where the action is much more regulated and gradual, but little pre- 
cautionas to length of time need be observed. Besides the difficulty 
of regulating its action, there are still other and grave objections to 
the use of sulphuric acid. One of these is that, no matter how care- 
fully the acid is added to the tissue, and no matter how quickly the 
washing in water is accomplished, there will be a very considerable 
evolution of heat attending the hydration of the acid, which is liable 
to accelerate its action and to cause very grave changes in such delicate 
structures as fine protoplasmic threads traversing the cell-wall. The 
folding up and general displacement of the tissue consequent upon the 
action of such a violent reagent also greatly increases the already 
existing complications which attend all observations connected with 
minute histology. 

For these reasons, while sulphuric acid is a very valuable reagent, 
both for swelling up resistent tissues on which chlor-zinc-iod has 
but little action, and for demonstrating in an unusually clear way the 
remarkable manner in which the apices of the protoplasmic processes, 
entering the pits, cling to the pit-closing membrane, it is, on the 
whole, the less satisfactory of the two, and the phenomena resulting 
from its action can only be rightly interpreted in the light of the 
more certain results obtained by the use of chlor-zinc-iod. For all 


640 SUMMARY OF CURRENT RESEARCHES RELATING TO 


tissues which will swell sufficiently under its action, the chlor-zinc- 
iod method may be regarded as perfectly satisfactory; after treat- 
ment with picric-Hoffmann’s-blue and subsequent washing with water, 
nothing but protoplasmic structures will be stained. In-clear instances 
where a thick closing membrane is plainly traversed by threads, it can 
be demonstrated with ease that, while the individual threads are well 
stained, the substance of the pit-membrane itself undergoes no colora- 
tion, even when the section has been exposed to the action of the dye 
for a long time. When the pits are smaller and the threads less 
clearly defined, it is more difficult to observe that the substance of the 
pit-membrane is still free from coloration ; and when, owing to the 
thinness of the closing membrane, all appearances even of striation 
cease to be recognizable, only an apparent staining of the entire 
membrane can be observed. Such staining points, however, in the 
opinion of the author, not to the coloration of the substance of the 
pit-membrane, but to the staining of protoplasmic threads traversing 
its structure. 

Besides a platinum lifter, the author uses platinum needles, and is 
careful thoroughly to brush all the sections with a camel’s-hair brush, 
both after the action of the acid or of chlor-zinc-iod and after 
staining. 

To prove that the threads traversing the cell-wall are actually pro- 
toplasm, he employed with success a solution of molybdic acid in strong 
sulphuric acid, which has the advantage of swelling the cell-wall and 
at the same time colouring the protoplasm. The solution is colourless 
and gives a beautiful blue colour with alcohol and many other organic 
substances; and this reaction is extremely delicate. While not 
affecting the cell-wall for some time this reagent gives at once a fine 
blue coloration with protoplasm. If a section of some living endo- 
sperm, such as that of Tamus, is treated with it, the cell-wall will 
swell up, and it will commence to dissolve the protoplasm ; the fine 
threads perforating the walls will remain for some time unaffected, 
but will soon be perceptibly coloured, while the main mass of proto- 
plasm will assume an intense blue. 

The pit-membrane itself possesses some properties different from 
those of the cell-wall. After staining with iodine and chlor-zinc- 
iod, while the cell-wall assumes the usual blue tint, the pit-mem- 
brane is but slightly coloured, and, when thin, appears as if not coloured 
at all, although the examination of a fine transverse section of the pit 
will prove that a definite staining has taken place. But the depth of 
the staining is less than might have been expected in proportion to the 
thickness of the membrane. Methylene blue stains both the wall and 
the pit-membranes a fine light blue, and, after the action of sulphuric 
acid, the swollen wall assumes a much lighter tint, owing to the fact 
that the quantity of the dye taken up by the cell-wall is now distri- 
buted over a larger space. If a section is cautiously treated with 
sulphuric acid, washed, and stained, it will be seen that, whereas the 
general swollen wall is coloured a light blue, the bottoms and the sides 
of the pit retain the darker blue colour of the unswollen cell-wall, and 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 641 


will thus be clearly marked out. If, however, another section is 
treated for a longer time with acid, or the same section is a second 
time exposed to its action, no special coloration of the bottoms and 
sides of the pits takes place on staining, but the whole swollen wall is 
of a uniform light tint. This shows that the substance of the pit- 
closing membrane and of the layers immediately surrounding the pit- 
cavity are more resistent than the rest of the cell-wall; as indeed has 
already been pointed out by Strasburger. 

Exactly the same phenomena are observed when a section, after 
cautious treatment with sulphuric acid, is stained with methyl-violet. 
In the case of methylene blue the protoplasm is not coloured, but 
when methyl-violet is used, a deep staining of that structure occurs, 
the tint of which is the same as that of the bottoms and sides of the 
pits; for, while the general cell-wall assumes a violet colour, the pro- 
toplasm, the pit-membranes and the sides of the pits appear of a deep 
purple. Now since protoplasmic processes from the main protoplasmic 
mass may project for some distance into the swollen pits, when such a 
stained section of pitted tissue is examined, it appears as if there were, 
in any two contiguous cells, threads of protoplasm of a purple colour 
traversing the thickness of the violet cell-wall by means of the pits, 
and thus establishing a direct continuity of the protoplasm from cell 
to cell. But after prolonged treatment with dilute glycerin, this 
purple colour dissolves from the pits, and the protoplasmic processes 
are left clearly seen, and may or may not be the means of establishing 
a continuity between the cells. As in the case of methylene blue, so 
also here, a more lengthy treatment of the tissue with acid will swell 
up the pit-membranes, and when in that condition the pits will assume 
the same colour as the rest of the cell-wall. 


Method of Preparing Dry Microscopic Plants for the Micro- 
scope.*—G. Lagerheim has found the following method convenient 
for the examination of alge or other plants which have already been 
dried. 

A fluid is prepared of the following composition :—1 part fused 
potassium hydrate is dissolved in 5 parts water, and when the solu- 
tion is complete 5-5 parts are added of glycerin of the consistency of a 
syrup. The dried desmids, Cidogoniacee or other alge, are treated 
with water till they are thoroughly moist; a small piece of the 
material is then taken up with a pincette and placed upon the glass 
slide. One or two drops of the fluid are added, and the alge 
distributed as evenly as possible with dissecting-needles. The glass 
slide is then warmed for a time over a spirit-lamp, and a cover-glass 
finally placed on. The potassium hydrate has now caused the 
previously shrunken alge to swell and resume their original form. 
The addition of glycerin gives a consistency to the fluid, so that the 
alge can easily be turned over by shifting the cover-glass, and thus 
observed on different sides, a point of great importance, for example, 
in the study of desmids. 


* Bot. Centralbl., xviii. (1884) pp. 183-4. 


642 SUMMARY OF CURRENT RESEARCHES RELATING TO 


The alge prepared in this way can readily be drawn or measured. 
The cover-glass is carefully removed, and, if a low power or a dis- 
secting Microscope is used, the object is taken up by a needle or stiff 
bristle, and again at once placed in potassium acetate or glycerin. 
Tf, on the contrary, the whole material thus prepared has to be got 
ready for drawing or measuring, a drop of acetic acid is added after 
removing the cover-glass. The alge are in this way imbedded in 
potassium acetate and glycerin, fluids perhaps the best adapted of 
any for the preservation of alge. 

Dry mosses and fungi may also be prepared in the same way. 


Chapman’s Microtome.*—A. B. Chapman has devised a micro- 
tome, which has for its cutting surface two parallel glass-plates 
cemented to a block of mahogany, through which is inserted a brass 
cylinder at right-angles to the glass plates; in this cylinder (which 
forms the “ well” of the microtome) an accurately fitted brass plug 
works, carrying on its top a flat-headed table-like piece which entirely 
prevents the imbedding agent from rising or turning round while the 
sections are being cut. The plug is moved up and down by a brass 
disk, which revolves between the block of mahogany and a similar 
block underneath. The brass disk is graduated on the edge of its 
upper surface, each graduation representing a movement of -0005 in. 
of the plug. The microtome has a base-board which can be firmly 
clamped to a table, and the whole is so conveniently arranged that 
every operation or adjustment can be made at once, the whole being 
in view on the table. 


Use of the Freezing Microtome.t—The tendency at the present 
time is to make all microscopic sections by the dry method after paraffin 
infiltration and imbedding; but no doubt there is a ‘place, and an 
important one, for the freezing microtome in practical histology, and 
in this note 8. H. Gage calls attention to what seem to him improve- 
ments in its use. 

Disliking greatly the disagreeable mess made by ice and 
salt, it occurred to him to take advantage of the device of plumbers 
to thaw out water and gas pipes,—to use strong alcohol with 
the ice or snow instead of salt. By using snow or finely powdered 
ice and 95 per cent. alcohol, a temperature of 20 C. below zero is 
obtained within five minutes, and this temperature may be maintained 
with far less trouble than with ice and salt. The microtome used is 
the Rutherford pattern, modified by placing the drain near the top 
instead of in the bottom. A rubber tube passing from this drain to 
a jar preserves the overflow. It requires about 250 c.cm. of 
alcohol to freeze and keep frozen one tissue for cutting, but this is 
not lost, as little evaporation takes place, and the dilution does no 
harm for many purposes, hence the method is not wasteful, while it is 
much more pleasant and expeditious than with salt. 

Ordinarily tissues are infiltrated with thick gum before freezing, 


* Sci.-Gossip, 1884, p. 137. 
+ Science Record, ii. (1884) pp. 134-5. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 643 


and then the sections are soaked in a relatively large amount of water 
to remove the gum. Evidently while soaking, staining, and trans- 
ferring the sections, especially if they be of such an organ as the 
lungs, there is every liability of their becoming folded or torn. This 
may be avoided by staining the tissue in the mass as for dry 
section-cutting, and then soaking in water to remove any alcohol, and 
finally completely infiltrating the tissue in a thick solution of very 
clean gum arabic. 

When ready to make the sections the well of the microtome is 
filled with the thick gum and the tissue introduced at the proper 
time as usual. Before cutting, the gum is cut away from the tissue 
as in sharpening very bluntly a lead pencil, then as the sections are 
cut they are transferred directly to the slide. After several slides are 
filled, a drop of glycerin is added to each section and the cover-glass 
applied. This is practically mounting in Farrant’s solution. 


Apparatus for Injection—Fearnley’s Constant-Pressure Apparatus. 
—Very great variety exists in the forms of this class of apparatus. In 
the majority of them the leading principle is the compression of the 
air in an intermediate vessel by the entrance into it of a liquid falling 
from a greater or less height according to the pressure required, the 
air then acting on the injecting fluid in another bottle communicating 
with the first. 

In the two following the intermediate vessel is dispensed with. 
Ranvier’s * (fig. 108) has a syringe connected by an indiarubber tube 


Fia. 108. 


with the bottle containing the injecting fluid, which is supported on 
a retort-stand. A second indiarubber tube terminates in the canula, 

Ludwig's t (fig. 109) acts by the fall of quicksilver drop by drop into 
the vessel, A, containing the injecting fluid I. 


* Thanhoffer’s ‘Das Mikroskop und seine Anwendung,’ 1880, p. 187 (1 fig.). 
+ Ibid., p. 188 (1 fig.). 


644 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Toldt’s * (fig. 110) is similar to the preceding, but in addition to 
the vessel containing the injecting fluid, a second air-vessel is 
introduced. 

Thanhoffer’s.t Prof. L. v. Thanhoffer uses the following apparatus 
(fig. 111). To the wall of the room and near the ceiling a board is 
fixed. This board carries a pulley, over which a cord is passed, having 
at one end a large glass vessel A, filled with water ; at the other end of 
the cord is a handle, by which the vessel can be drawn up and down 
as required. When the tap in Ais open, water flows through the india- 


Fie. 109. Fig. 110. 


= 
eS 


Vf 
| 


rubber tube into a second vessel B, which acts as an air-reservoir. 
The air compressed in B passes into C, which contains the injecting 
fluid, and forces it through the discharge pipes and thence into the 
vessels. The pressure is of course increased according as A is raised. 
The amount of pressure is denoted by the manometer M. Quicksilver 
may be substituted for water, and greater pressure thereby obtained, 


. Thanhoffer’s ‘Das Mikroskop und seine Anwendung,’ 1880, p. 189 
(1 fig.). 
+ Ibid., pp. 190-2 (1 fig.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 645 


but in injecting fine vessels this is quite unnecessary, for if the room 
be sufficiently lofty a pressure of from 300 to 400 mm. can be obtained 


Hie. 111, 


SS 
CATALAN TD 


PUTY ODIO UV ULUOUUUIUVNDUNE UNNI 
VTE TT 


ITA 


by drawing the vessel A to the ceiling, a pressure which is more than 
is required. 


646 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Ludwig's * (fig. 112) for quicksilver and small pressure, is substan- 
tially identical, and requires no explanation beyond the figure. 


Fig. 112. 


SSS aaa 
TRDDIT CAN OUTDATED 


* Thanhoffer’s ‘Das Mikroskop und seine Anwendung,’ 1880, pp. 192-3 (1 fig.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 647 


Ranvier’s * (fig. 113) consists of a glass vessel filled with quicksilver 
which can be raised and lowered on a retort-stand. The rise of the 
quicksilver in the intermediate vessel compresses the air which it 
contains as well as that in the bottle containing the injecting fluid, 
which is forced out as in the previous case. In another form (fig. 114) 


Fig. 114. 


the pressure is obtained by compression of an indiarubber ball K 
communicating with an air-reservoir R (M being a manometer). 
Hering’s + (fig. 115) consists essentially of two glass bulbs, A A’, 
having a thin glass tube pass- 
ing through the stoppers in Fia. 115, 
their necks, and by which the 
bulbs communicate with each 
other. A flexible tube from 
each bulb passes into one or 
other of the bottles E E, con- 
taining the injecting fluid. 
The ends of the glass tubes 
are drawn out so fine that the 
quicksilver passes only a drop 
at a time from one to the other 
(even when the air is com- 
pressed). When the bulbs are = 
turned on their axis, and in- & IOCOUTY OOO TOONS VON T OOOO CTD OOOO OC OTTO 
stead of the horizontal posi- 
tion I., take the oblique one II., the quicksilver will flow from A to 
A’, and compress the air in the bulb A’, and act upon the injecting 
fluid in the vessel E. The nearer a vertical position is approached, 
the greater the pressure will be by which the injecting fluid is forced 
into the blood-vessels. The two bottles, E and E, are alternately 
used according as one or the other of the bulbs is uppermost. 


* Thanhoffer’s ‘Das Mikroekop und seine Anwendung,’ 1880, pp. 189-90, 
187-8 ¢ figs.).. 

+ Ibid., pp. 193-4 (1 fig.). 

t The figure, which is a cliché of the original, should have indicated one of 
the two positions of the bulbs by dotted lines. As drawn, there appear to be four 
bulbs. B, ©, and D are not explained but their function is obvious, 


648 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Other forms are described by Dr. P. Latteux in his ‘Manuel de 
Technique Microscopique.’ 

Da ee * (fig. 116) consists of a copper globe B, to hold the 
compressed air, having a tube at A with mercury serving as a mano- 
meter. Four taps are inserted in the globe of which one is the air 


iniges, TWIG, 


FSS) Fee Bt Eat et SS 


tube from the indiarubber ball C, another regulates the pressure, 
and the third and fourth H E communicate with two bottles F F 
containing carmine and blue, the exit tubes G H from these bottles 
terminating in canul for insertion in a vein and artery, or artery and 
gland duct. 


= o utae P., ‘Manuel de technique microscopique,’ 2nd ed., 1883, pp. 110-12 
g.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 649 


The apparatus is sufficient to completely fill the finest vessels of 
the retina, spinal cord, &c. 

Fearnley’s Constant-Pressure Apparatus.*—The method of Ludwig 
has always been acknowledged as superior to injecting by the syringe 
except for the one great obstacle—applying the necessary pressure, 
which had to be effected by elevating and depressing huge water- 


Fig. 117. 


bottles or by connecting the air-pressure bottle with a water-tap and 
regulating the pressure as best one could, thus rendering the pressure 
almost as uncertain and irregular as the thumb-pressure of the 
syringe. Mr. W. Fearnley’s method is to apply the pressure with an 
ordinary Higginson’s enema syringe (figs. 117 and 118). 

No practice is required with this simple contrivance beyond 
introducing and tying in the nozzle in the aorta. 


* Brit. Med. Journ., 1883, pp. 859-60 (2 figs.). 
Ser. 2.—Vou. IV. 2x 


650 SUMMARY OF CURRENT RESEARCHES RELATING TO 


There is a bath, having a shallow part for the animal to lie in, 
and a deeper part for the Woulff’s bottle, containing the injection- 
mass, to stand in. A large (40 ounce) Woulff’s bottle, with three 
necks, is fitted with three perforated indiarubber stoppers. ‘The 
middle stopper is perforated with a glass tube which goes to the 
bottom of the bottle. Each of the others is perforated with a glass 
tube, the depth of the stopper only, and standing above the stopper 
sufficiently to admit of a piece of indiarubber tubing being fixed 
upon it. The Woultf’s bottle containing the mass has two necks, 
fitted with indiarubber stoppers. One neck admits a piece of glass 
tube, which goes quite to the bottom of the bottle; the other admits 
a short piece of tube the depth of the stopper only. Fig. 117 shows 
all further detail. 

The mercurial manometer allows five inches rise of the mercury 
in the ascending arm—therefore five inches fall of the descending arm 
—though four inches will do. 

“To inject an animal, a rabbit, for instance, proceed as follows :— 
Fill the bath with water, and heat the water with a Bunsen’s burner 
to 100° Fahr. or so. The Woulff’s bottle containing the mass should 
be filled and thoroughly stoppered. Then chloroform the rabbit and 
make an L-shaped incision into the thorax, so as to expose the heart 
and aorta. This is done by cutting up the middle line of the sternum 
(breast-bone) as far as the root of the neck nearly, then making a second 
incision at right angles to this to the rabbit’s left. A triangular flap 
is thus made, and the heart inclosed in the pericardium exposed. 
Having cut through the pericardium, seize the apex of the heart with 
a pair of forceps and snip it off, then the heart’s apex appears as in 
A, fig. 118. That is to say, the right and left ventricles are opened, 
and the animal instantly bleeds to death. Mr. Fearnley uses a nozzle, 
as in B, Fig. 118, which has an elastic collar ec, which is plugged by 
a nozzle, as here shown. 

The opening in the right ventricle leading to the pulmonary 
artery has a crescent shape or slit-like appearance; whilst the opening 
in the left ventricle, leading to the aorta, is round, Therefore, if we 
wish to inject the entire arterial system, we insert our nozzle into 
the round hole; but if we wish to inject the pulmonary system only, 
we choose the crescentic slit. 

Hither glass nozzles,* or those shown in fig. 118, are to be inserted 
into one or other of the two holes (usually the round one for injecting 
the entire arterial system with carmine and gelatine mass). We can 
now either tie the artery only, or we can tie the whole heart substance. 
In either case a ligature of floss silk is to be passed round (the artery 
or the entire heart) and tightly tied and secured. Before proceeding 
further, we wash out the cavity of the thorax of all blood to keep our 
bath water clean, then we lift the animal into the bath and there let 
it remain ten minutes or so to get well warmed. It is a good plan 
to slit open the entire abdomen in the middle line, so as to allow the 


* Mr. Fearnley informs us that he now uses glass nozzles with tube connec- 
tions, which answer quite as well as those figured, and are cheaper. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 651 


warm water to freely get round the abdominal contents: the mass 
thus gets into every organ and into every part of an organ evenly. 

We now connect the pressure bottle with the manometer and with 
the Higginson’s syringe, as shown in fig. 117, also with the mass 
bottle. The tube of the mass bottle, which is to convey the mass 
away from the bottle, is now clamped, as shown at O, fig. 118, and 
must never for an instant be allowed to get out of the warm water 
into the cold air. 


Fic. 118. 


Having our small basin full of water, we now squeeze the Higgin- 
son’s syringe, watching the manometer, to raise the mercury half an 
inch. This done, we remove the clamp from the efflux tube, and the 
red fluid after driving out a few air-bubbles begins to flow out; we 
at once make the connection, and all quicksands are passed if we have 
tied in our nozzles properly into the artery and the connecting part, 
and fastened in our stoppers thoroughly into our Woulft’s bottles. 

Our task is easy now: all we do is to seize the head of the animal, 
which should be to our left, with our left hand, to watch the pale 
gums, tongue, and eyelids become suffused with a pale blush which 
gradually deepens, whilst we gently squeeze and relax the barrel of 
the syringe and glance at the mercury from time to time. When the 
mercury has risen four, or at most five inches, the whole animal will 
be completely injected: the visible mucous membranes and bowels 
will be dark-red and much swollen. 

We now remove the animal, and place it in ice-cold water under 
@ common water-tap for an hour or two, and divide it into parts as 
required. This method of applying pressure is wonderfully delicate ; 
thus, whilst we can raise the mercury in the manometer almost imper- 
ceptibly, one entire compression of the barrel raises the mereury 
one inch.” 

ana 


652 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Myrtillus for Staining Animal and Vegetable Tissues.*— Dr. M. 
Lavdowsky (in furtherance of the modern fashion of recommending 
every conceivable substance which by any chance will furnish a 
stain) recommends the berries of Vaccinum myrtillus, as an excellent 
staining agent for the nuclei of all cells and the cellulose walls of 
plant-cells. The karyokinetic figures are shown very plainly... 

The fresh berries should be well washed in water, the juice 
squeezed out and mixed with two volumes of distilled water, to 
which some alcohol (90 per cent.) has been added. It is then heated 
for a short time, and filtered warm. For use, a small quantity of 
the fluid should be diluted with two or three times its bulk of dis- 
tilled water. 

The stain gives a red (carmine) colour with fresh neutral objects, 
or lilac (hematoxylin) when the acid of the fluid is neutralized by 
an alkali or neutral salt. The latter is the more durable. A double 
stain is obtained by placing the object in a solution of eosin after 
treatment with the lilac stain. Directions are given for applying the 
fluid, but it does not appear to us, from the author’s own showing, 
to be a valuable or even useful addition to the already long list of 
staining agents. 


Hartzell’s Method of Staining Bacillus tuberculosis.t—A small 
quantity of sputum is spread as thinly and evenly as possible upon a 
slide, and allowed to dry, and is then passed slowly several times 
through the flame of an alcohol lamp or Bunsen burner. One or two 
drops of the fuchsin solution recommended by Gradle (prepared as 
follows: carbolic acid 15 minims, distilled water 1/2 fluid oz., 
dissolve, and add saturated alcoholic solution of fuchsin 1/2 fluid dr.) 
are placed upon the sputum, and allowed to remain from three to five 
minutes. The slide is now washed thoroughly with distilled water, 
to remove the excess of fuchsin, and the stained sputum completely 
decolorized by a saturated solution of oxalic acid. It is again 
thoroughly washed in distilled water, and allowed to dry; it is now 
ready to be mounted in glycerin or balsam for examination. With a 
power of 500 or 600 the bacilli will appear as brilliant red rods, no 
staining of the background being necessary. 

One chief advantage claimed over other methods is that in the 
latter the decolorizing agent employed is dilute nitric acid ; but this, 
besides being disagreeable to handle because of its corrosive and 
staining properties, is apt to remove the colour from the bacilli too, 
unless great care is taken. Oxalic acid, however, seems to leave the 
dye untouched in them. 


Safranin Staining for Pathological Specimens,t—For staining 
tumours, Dr. V. Babes(in) recommends that fine sections of tissue 
hardened in alcohol or chromic acid should be steeped either in a 
solution of safranin which has been dissolved in warm water, or in a 
mixture of equal parts of concentrated watery and concentrated 


* Arch. f. Mikr. Anat., xxiii. (1884) pp. 506-8. 
+ Amer. Mon. Micr. Journ., v. (1884) pp. 76-7, from ‘ Medical Times.’ 
{ Arch. f. Mikr, Anat., xxii, (1883) pp. 356-65. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 653 


alcoholic safranin solution for half an hour; they should be washed 
slightly in water, and then dehydrated as quickly as possible by 
absolute alcohol, then transferred to turpentine and mounted in 
balsam. Some tissues which are not so readily decolorized may be 
clarified with oil of cloves. Although they appear scarcely red, yet 
such sections show the following structures: viz. nucleoli of white 
blood-corpuscles; granules in the same and in most cells of rapidly 
proliferating granulating tissues; periphery of red blood-corpuscles ; 
filamentous bodies occurring in connection with blood-vessels in 
process of formation; nuclei of giant-cells and nucleoli of all large- 
celled sarcomata and carcinomatous tumours. 

As the inactive, skeletal part of the nucleus is not stained by the 
safranin, it is easy to follow by its means the part which the nucleolus 
plays in cell-division. In large-celled, malignant tumours a great 
variety of forms are thus brought out in the nucleus, while the 
spindles and the fibrils connecting them remain uncoloured. In 
melanosarcoma the fission-stages of the cells, which remain concealed 
under every other treatment, are well brought out, and in rapidly 
growing small-celled tumours, e. g. lymphosarcomata, the appearance 
of universal staining is imparted to the cell by a series of delicate 
nuclear markings which almost fill the cell. 

Secondly, for investigating the structure of the cell and of other 
histological elements a super-saturated solution should be employed ; 
it is warmed to 60°, and filtered in this state; the sections are placed 
in a small quantity of the liquid in a watch-glass, which is then 
warmed * for a few seconds over a spirit-lamp until the precipitating 
crystals are redissolved; the sections are left for a minute, then 
washed in water, and treated as in the former case. Tissues which 
do not stain readily should be warmed again and again. The nuclear 
netsork comes out well under this treatment. It is especially 
adapted for delicate structures and for bacteria; every micrococcus 
appears brownish-red, while the surrounding tissues assume a fine 
rose-red ; the bacilli of tuberculosis and lepra are not thus stained. 

Thirdly, the sections may be left for 12 to 24 hours in the solu- 
tion (either concentrated watery or alcoholic, or a mixture of the two). 
Sections thus coloured may be left, if necessary, somewhat longer in 
alcohol, turpentine, oil of cloves, or, better, origanum ; a large number 
of details are thus brought out, and a similar effect is produced by 
longer action of a watery solution; the method is especially adapted 
to tumours of the brain or spinal cord. 

The finest representations of the changes undergone by nuclei in 
fission were produced by rapidly staining with safranin, followed by 
eosin, and mounting in balsam. Safranin and hematoxylin bring 
out the nuclear skeleton violet and the nucleolus red. Preparations 
made according to these methods have proved durable. Some points 
are better seen by mounting in glycerin, but the colour disappears 
more or less in time, and acetate of potash is preferable both on the 
grounds of permanency and clearness. 


* Of. this Journal, iii, (1883) p. 918. 


654 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Preparations which show only the muscular fibre and the elastic 
tissue may be made by staining small fragments with a mixture, half 
and half each, of oil of cloves or origanum and concentrated alco- 
holic solution of safranin and placing for an hour under the air- 
pump: sections may then be made at once, or, better, uncoloured 
sections may be transferred from alcohol to the oily solution; the 
sections are washed with solutions of caustic potash in alcohol, and 
mounted in acetate of potash. By putting sections stained with 
safranin into 30 to 40 per cent. solution of caustic potash the colour 
is fixed, and the elements come out very distinctly ; they should be 
mounted in acetate of potash. 


Collodion as a Fixative for Sections.*—Sections fixed by means of 
a solution of collodion in clove oil, as suggested by Schallibaum,yt 
may be coloured on the slide. S. H. Gage, who had begun to experi- 
ment with collodion before Schallibaum’s method was published, 
recommends that the collodion and clove oil be applied separately. 

«A solution of collodion is prepared by adding to 2 gr. of gun- 
cotton (that used by photographers is good) 54 ce. of sulphuric ether 
and 18 ce. of 95 per cent. alcohol. After the gun-cotton is entirely 
dissolved the solution should be filtered through filter-paper or 
absorbent cotton. The slides are coated by pouring the collodion on 
one end, allowing it to flow quickly over the slide, and off the other 
end into the bottle. The prepared slides should be kept free from 
dust. As the collodion will not deteriorate after drying on the slide, 
any number of slides may be prepared at the same time. Before 
using a slide it should be dusted with a camel’s-hair brush, and with 
another brush the collodionized surface of the slide should be thinly 
painted with clove oil. . . . . The sections are arranged as in 
the shellac method. The slide is warmed over an alcohol lamp, and 
then heated in a warm chamber, so as to drive off the clove oil. After 
cooling, it may be placed in a wide-mouthed vial of turpentine, 
chloroform, xylol, or refined naphtha, to remove the paraffin. 
Naphtha is very cheap, and is the best agent we have yet tried for 
dissolving the imbedding mass. The sections are usually freed from 
imbedding mass within half an hour, though the slide may remain in 
any of the solvents mentioned for two or three days, or perhaps 
indefinitely, without loosening the sections. When the slide is 
removed from the naphtha, the sections are washed with 95 per cent. 
alcohol by means of a medicine dropper, or by immersing the slide 
in alcohol. If the sections are to be stained in Kleinenberg’s hema- 
toxylin, or in any other stain containing 50 per cent. or more alcohol, 
the slide is transferred directly from the aleohol used for rinsing to 
the staining agent; otherwise it should be first transferred to 50 per 
cent. alcohol, and from that to the staining agent. Whenever the 
sections are sufficiently stained, they may be mounted in any desired 
mounting medium. In case Canada balsam is to be used, the slide 
must be immersed in alcohol to wash away the stain, and finally in 


* Medical Student (N. Y.), i. (1883) pp. 14-6. 
t See this Journal, iii. (1883) p. 736. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 655 


95 per cent. alcohol to completely anhydrate the sections. They are 
cleared with a mixture of carbolic acid 1 part, turpentine 4 parts. 
The balsam to be used is prepared by mixing 25 gr. of pure Canada 
balsam with 2 cc. of chloroform and 2 ce. of olive oil. The latter 
very soon removes any cloudiness that may have appeared in the 
collodion film.” 


Piffard’s Slides.—Mr. B. Piffard has patented a slide which is 
made by forming with a diamond a round recess in an ordinary 
slide. In this the object is placed, and covered with thin glass. The 
upper surface of the slide is thus perfectly smooth, the cover-glass 
being even with the slide. There is no danger of the cover-glass 
and object being knocked off; and the recess causes a very beautiful 
diffusion of light. 


Mounting in Balsam in Cells.*—R. P. H. Durkee describes the 
following process :—A curtain-ring, flattened by pressure, is placed 
upon a clean slide and the slide placed on the hot table. Drop in 
the centre a small portion of balsam, enough to fill the cell, and heat 
till the air-bubbles rise and permit of breaking with the needle; at 
the same time gently moving the ring about, and pressing it down to 
insure contact with the slide. Place the object in the balsam, 
taking care to see that it is completely covered ; warm the cover and 
place it in position, in doing so holding it in the forceps parallel 
with the surface of the slide, so as to expel the air all round. Weight 
down with a bullet, and apply heat as may be necessary to harden 
the balsam. 

What the author considers a feature is that there would seem to 
be no possibility of varnish running in, the channel in the top of the 
ring receiving the excess of balsam when pressed out by the cover, 
and thus forming a barrier to the influx of the varnish used in ring- 
ing. For flattening the rings he used two plates of brass, 24 in. 
square by 1/8 in. thick. Place the rings, six or more at a time, 
between the plates, and press in a lever stamp. This method of 
mounting seems to him to have the following desirable features, viz. 
no previous preparation and drying of cells, rapidity and neatness of 
finish, and no running in of varnish. 


Styrax, Liquidambar, Smith’s and van Heurck’s Media. —Dr. 
H. yan Heurck writes that styrax, when prepared by exposing the raw 
product to the air and light, dissolving and filtering, is no longer of 
a dark colour, and that its index is higher than 1°585, as given on 
p. 475. The purified styrax of commerce is always darker and of 
lower refractive index. Preparations become completely colourless 
at the end of a few months, especially if brought into the light occa- 
sionally, and the index rises a little. 

Liquidambar can be obtained of Lamman and Kemp, William 
and Cedar Streets, New York. It must be heated to reduce its 
brittleness, and dissolved by means of the water-bath in a mixture of 


* Amer. Mon. Mier. Journ., v. (1884) pp. 84-5. 


656 SUMMARY OF CURRENT RESEARCHES RELATING TO 


alcohol and benzine, and filtered. This is also the best solvent for 
styrax. 

; Styrax and liquidambar, purified and prepared according to Dr. 
van Heurck’s directions, can be obtained of Messrs. Rousseau, 42- 
44, Rue des Ecoles, Paris. 

Prof. Smith’s medium, while most excellent for difficult diatoms 
of delicate structure, is not better than styrax for ordinary diatoms 
and preparations of histology or of insects. 

Dr. van Heurck also announces that he has discovered a colour- 
less medium analogous to that of Prof. Smith, but with an index 
higher than liquidambar. 


Grouping Diatoms.*—J. Deby calls attention to some slides pre- 
pared for him by Moller, each containing many species of the same 
genus arranged in several lines. Thus there are 72 species or varie- 
ties of Triceratium, 60 of Nitzschia, 45 of Surirella, 38 of Epithemia, 
&c. Such slides have, Mr. Deby considers, enormous advantages 
over the “type-plates” from the point of view of the comparative 
study of the species of a genus. Equally to be recommended, from 
a scientific point of view, is, he thinks, the plan by which as many 
species as possible from the same gathering are united in one slide. 


Quantitative Analysis of Minute Aerial Organisms.t—In the 
reports of the Imperial German Board of Health is a paper on this 
subject by Dr. Hesse. He employed an apparatus, which in all essen- 
tials so corresponds with the portable aéroscope of Dr. Maddox 
described in this Journal, III. (1883) p. 388, that it is necessary to 
note the fact, as no reference is made to it by Dr. Hesse. Instead, 
however, of drawing the air direct into an aéroscope and on to a thin 
cover-glass smeared with a glutinous substance for examination of 
the deposited matter by the Microscope, a long tube lined with a 
layer of gelatine is used. The air is allowed to enter by an aperture 
at one end, that most suitable being of like diameter with that of 
the exit tube, and as it traverses the tube slowly it deposits the 
organisms in its passage. 

According to the nature of the deposits, small colonies are deve- 
loped in the gelatine at different parts of the tube. By employing a 
long tube and slow traverse of air, the bacteria are deposited before 
reaching the exit, while the fungi—mildew and spores—appeared more 
abundant at the exit end than at the entrance. That bacteria are 
rapidly deposited in tranquil spaces was long since shown by Professor 
Tyndall. 


Microscopical Evidence of the Antiquity of Articles of Stone.{ 
—An action has recently been pending in New York as to the genuine- 
ness of the collection of antiquities brought from Cyprus by Count Di 
Cesnola and sold to the city. 

Mr. B. Braman, President of the New York Microscopical Society, 


* Journ. de Microgy., viii. (1884) pp. 230-1. 
+ MT. aus dem K. Gesundheitsamte, ii. Berlin, 188+. 
a t ae Mon. Micr. Journ., y. (1884) pp. 14-5, from New York Times, 22nd 
ec., . 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 657 


was examined as a witness and detailed the result of his examination 
with the Microscope of the surfaces of the statues in the collection. 

“The Cypriote stone whereof these statues are sculptured is a 
cellular calcareous tufa. The cells are minute and crowded. There 
are about 1500 to the square inch. They are spherical in shape, and 
about 1/100 in. in diameter. When freshly cut, it will be 
found that the walls of some cells are harder than the walls of others. 
The hard walls resist the effects of the atmosphere with more success 
than the softer ones. During exposure these soft spaces sink first, 
and leave the hard ones standing, like craters on the face of the moon. 
The soft spaces sink into dome-like shapes, and small orifices indicate 
that the atmosphere has begun to affect them. Then the cups thus 
formed are carried away, the hard projections roll off in small globes, 
and the process recommences. Hach process occupies several centuries. 
In the case of buried objects in Cyprus, the water filtering through the 
ground makes a deposit on them, more or less thick, of carbonate of 
lime. I have given seven or eight hours to the microscopical 
examination of the statuette of Venus, and it is susceptible of 
scientific demonstration that the surface of the so-called mirror and 
the surrounding surface are ancient. On the mirror are eight stipples 
of carbonate of lime, deposited in the way I have stated, which are an 
integral part of the ancient surface, and would not appear on a freshly 
cut surface. These evidences of antiquity could not be taken away 
without breaking the stone. They fill the cavities whereof I have 
spoken. They appear on the surface of the drapery within 3/16 in. of 
the mirror’s outline. My Microscope would have disclosed cement 
1/1000 in. in thickness.” 


“ B.Se.”—Carbolic Acid and Cement. 

{Fresh-water Algze mounted three years ago in a weak carbolic-acid solu- 
tion with asphaltum for the cement are still perfectly good.] 
Sci.- Gossip, 1884, p. 137. 

Brant, T. J.—Notes on putting up Microscopic Objects. 

Rep. South Lond, Mier, and Nat, Hist, Club, 1884, p. 13. 

Chapman’s (A. B.) New Microtome. 

[Supra, p. 642.] Sci.-Gossip, 1884, p. 137. 

Coxe, A. C.—Methods of Microscopical Research. 

Part XI. Mounting (continued). pp. lvii—lxi. (Mounting the Diatomacee. 
Cleaning and Mounting Polycystina. Preparation and Mounting of 
Insects. Preparation of Vegetable Sections, To Double Stain Vegetable 
Sections.) 

Part XII. pp. Ixiii-lxxii. On Microscopical Drawing and Painting (by 
Ber D:)- 
es Popular Microscopical Studies. IX. pp, 39-42, The Crane Fly 
(Tipula Oleracea). Plate 9 x 40. 

No. X. pp. 43-6. Sponge. Plate 10. 

No. XI. pp. 47-52. Starch. Plate 11 (Sarsaparilla officinalis x 400). 
me Studies in Microscopical Science. 

Vol. Il, No. 19. Sec. I. No. 10. pp.37-40. Nerve of Horse. Plate 10, 
at, oe LO. 

No. 20. Sec. II. No. 10. pp. 39-42. Vascular Tissue (continued). Plate 10, 
Wood Vessels and Cells. 

Vol. II. No. 21. Sec. I. No. 11. pp. 41-4. Human Cerebellum, Plate 
11, 7.8.5. 150: 

No. 22. Sec. II. No. 11. pp. 43-6. Fundamental Tissue. Plate 11. 
T.S. Petiole of Limnanthemum x 75. 


658 SUMMARY OF CURRENT RESEARCHES RELATING TO 


D., E. T.—See Cole, A. C. 
Decker, F.—Hin neuer Schnittstrecker. (A new section-smoother.) [ Post.] 
Arch. f. Mikr. Anat., XXIII. (1884) pp. 537-43 (2 figs.). 
Francorte, P.—Description des différentes méthodes employées pour ranger les 
coupes et les diatomées en séries sur le porte-objet. (Description of the 
different methods adopted for mounting sections and diatoms in series on 
the slide.) Continued. Bull, Soc. Belg. Micr., X. (1884) pp. 137-41. 
e se Petit instrument qui permet de repasser sur le cuir les grands 
racoirs du Microtome de Thoma. (Small apparatus for sharpening on the 
strop the large razors of Thoma’s Microtome.) [Post.] 
Bull. Soc. Belg. Micr., X. (1884) pp. 151-2. 
FRIEDLANDER, C.—Microscopische Technik zum Gebrauch bei medicinischen und 
pathologisch - anatomischen Untersuchungen. (Microscopical Technic in 
medical and pathological-anatomical researches.) viii. and 123 pp. and 1 pl. 
Qnd ed. 8svo, Berlin, 1884. 
Grirrin, A. W.—On the Collection and Preparation of the Diatomacexe. Part I. 
Collection. 

(“An attempt to gather together some of the ideas of the best authorities 
on the question, for the benefit of those whose want of leisure precludes 
them from searching out these facts for themselves.” | 

Journ. of Micr., III. (1884) pp. 188-46. 
Hitivovusr, W.—Preparing Schultze’s Solution. [Post.] 
Proc. Cambridge Phil. Soc., LV. (1883) p. 399. 
Hiroxcock, R.—Microscopi¢al Technic. V. Mounting in gelatinous and resinous 
media, Amer. Mon. Micr. Journ., V. (1884) pp. 109-12. 
See Insects, catching small. 
es ra See Mounting, questions about. 
Insects, catching small. 

[Mounting needle bent into a hook and dipped in alcohol. Dip the needle 
into alcohol (or concentrated carbolic acid—-R. Hitchcock) to free the 
insects. | 


39 ” 


Amer. Mon. Micr. Journ., V. (1884) p. 118. 
JACKSON, H. E.—Mounting the Skin of a Silkworm. 

[Soak in acetic acid for 10 days, then open carefully with scissors from anus 
to mouth and wash in water. Soak in weak and then strong alcohol, 
follow with oil of cloves, turpentine, and balsam.] 

The Microscope, IY. (1884) p. 1338. 
Kipper, J. H.—An examination of the external air of Washington. 

[Describes and figures an aéroscope in principle “not essentially different 
from those devised by Pouchet, Maddox, and Cunningham.” By bending 
the tube of the funnel at right angles the glycerine is prevented running 
off, as is the case when the smeared glags is set vertically. ] 

Journ. of Micr., III. (1884) pp. 182-5 (1 pl.). 
Kinesiey, J. §.—Microscopic Methods. I. 
[No. II. was given ante, p. 484, the Part containing I. having been lost in 
the post. | 
III. Hardening and macerating. 
Science Record, II. (1884) pp. 108-10, 155-60. 
Lavpowsky, M.—Mpyrtillus, ein neues Tinctionsmittel fir thierische und 
pfilanzliche Gewebe. (Myrtillus, a new staining medium for animal and 
vegetable tissues.) [Supra, p. 652.] 
Arch. f. Mikr, Anat., XXIII. (1884) pp. 506-8. 
Loew, O.—Ueber den mikrochemischen Nachweis von Hiweissstoffen. (On the 
microchemical analysis of albuminous substances.) [ Post.] 
Bot. Ztg., XLII. (1884) p. 273. 
Mounting, questions about. 

[As to the cracking of the covers of Moller’s slides; also as to bubbles, and 
note by R. Hitchcock. “Bubbles are occasionally left in fluid mounts, 
especially when the cells are deep, under the impression that the air 
they contain being very elastic prevents injury to the cell from internal 
pressure when the temperature rises. We confess to grave doubts if such _ 
bubbles are of any benefit whatever.”] 

Amer, Mon, Micr. Journ., V. (1884) p. 119. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 659 


Necri, A. F.—Coloration des Spores dans les Bacilles de la Tuberculose. 
(Staining the spores of the Bacilli of Tuberculosis.) [Post.] 
Journ. de Microgr., VIII. (1884) pp. 349-51, from ‘ Lo Sperimentale.’ 
Piffard’s (B.) Improved Microscopic Slides. [Supra, p. 655.] 
Sci.-Gossip, 1884, p. 136. 
PoiecnanD, M.—The Microscope in Paleontology. [Post.] 
Journ. of Micr., III. (1884) pp. 163-70 (1 pl.). 
Prinz, W.—Examen microscopique (1) d’une feuille de papier qui a servi & isoler 
les plaques du parafoudre de la station de Lebbeke; (2) des lames minces 
d’un morceau de poterie. (Microscopical examination (1) of a piece of paper 
used to isolate the lightning conductor of the station of Lebbeke; (2) of thin 
plates from a piece of pottery.) 
Bull. Soc. Belg. Micr., X. (1884) pp. 152-4 (3 figa.). 
Rawpu, T. S.—Results of a Microscopical Investigation of the action of Ammonium 
Molybdate and other chemical agents on the vascular and cellular tissues of 
about 120 different plants. Journ. of Micr., III. (1884) pp. 155-62. 
Ratasoct, J.—Les Diatomées. Récolte et préparation. (The Diatomacee. 
Collection and preparation.) Continued. 
‘ Journ. de Microgr., VIII. (1884) pp. 342-5. 
Rogsox, M. H.—Improvements in Microscopic Slides. 
a? experiments of five years ago to make slides similar to Piffard’s, 
supra. 
Sci.-Gossip, 1884, p. 162. 
Section-smoother, a simple. 
[Practically identical with P. Francotte’s, ante, p. 315.) 
Science Record, II. (1884) p. 112 (1 fig.). 
Sippa.L, J. D.—The Microscopical Examination of Milk and Drinking Water. 
Micr. News, IV. (1884) pp. 187-9. 
Stack, H. J.—Pleasant Hours with the Microscope. 
[Examining flowers of Borage, Comfrey, &c.—Ixodes. ] 
Knowledge, V. (1884) pp. 430-1 (2 figs.), 472-3 (2 figs.). 
StowELL, C. H.—Studies in Histology. III. Section Cutting. 
The Microscope, 1V. (1884) pp. 123-7. 
+» _ New Apparatus. 


” 

(Griffith’s Turntable, post. German Microtome. } 

The Microscope, TV. (1884) pp. 131-2. 
Tay.Lor, T.—Clearing fluid. 

[About equal parts of Squibb’s absolute alcohol and Eucalyptus oil forms a 
very good clearing fluid for animal or vegetable tissues. When the tissues 
are freshly cut, place them in commercial alcohol for afew minutes. Next 
transfer them to the clearing fluid, as above described, for a period of 
about ten minutes. They are next placed in pure Eucalyptus oil, which 
removes the alcohol; a few minutes’ immersion will suffice. It is not 
well to keep tissues longer than necessary in the fluid. Vegetable tissues 
become hardened when kept several days in it.] 

Amer. Mon. Micr. Journ., VY. (1884) p. 119. 
Unpernih, H. M. J.—Mounting Infusoria. 

[Reports his failures with osmic acid, permanganate of potash, and “ chromic 
oxydichloride” acid.]} 

Sci.-Gossip, 1884, p. 162. 
White Zinc Cement. 

[Note on the difference of opinion between Mr. R. Hitchcock and Professor 
C. H. Stowell, ante, p. 485. “Perhaps they are not speaking of the 
same preparation of white zinc.”] 

Micr. Bull., I, (1884) pp. 28-9, 


© G30) 


PROCEEDINGS OF THE SOCIETY. 


Mertine or 1llta Junz, 1884, ar Kina’s Cotten, Stranp, W.C., 
THE PrestpeNt (THE Rev. W. H. Dautinerr, F.R.S.) In THE 
CHarr. 


The Minutes of the special and ordinary meetings of 14th May 
last were read and confirmed, and were signed by the President. 


The List of Donations (exclusive of exchanges and reprints) re- 
ceived since the last meeting was submitted, and the thanks of the 


Society given to the donors. 

From 

Heurck, H. van.—Synopsis des Diatomées de Belgique—Table 
Alphabétique. 120 pp. 8vo, Anvers, 1884 .... . 

James, J. B.—Aids to Practical Physiology. viii. and 24 pp. 

ByO, Womloms, WI so 55 00 60 «80st 


The Author. 
Mr. Williams. 


Mr. Crisp called attention to the extraordinary character of the 
latter book, and read extracts from it (supra, p. 629). 


Mr. Crisp described Prof. Zenger’s method of constructing 
“« Hndomersion ” objectives by using a mixture of ethereal and fatty 
oils, which he claimed enabled the chromatic aberrations to be much 
more effectively dealt with (supra, p.616). He exhibited an objective 
sent by Prof. Zenger. 

Mr. J. Mayall, jun., in reply to Mr. Crisp, said that he had 
examined the objective exhibited, and found that it was not a 1/50in., 
as claimed, but in truth not more than 1/8 in. He also found that 
the spherical aberration was very imperfectly corrected. 


Dr. Wallich briefly described his new condenser, which he ex- 
hibited in operation at the close of the meeting. 


Mr. B. Piffard’s new slide was exhibited and described by Mr. 
Crisp (supra, p. 655). 


Mr. J. Mayall, jun., exhibited and described a simple mode of 
applying amplifiers to a Microscope (supra, p. 607). Several methods 
had been devised, and the one by Tolles was no doubt very good, but 
it was expensive. For the form which he now showed he did not claim 
any originality, because he remembered to have seen the same plan 
adopted, though in scarcely so simple a manner. His was simply a 
slide with three concave lenses, which could be pushed through the 
tube of the Microscope, so.that either could be used as required. By 
this means the working distance could be increased by 75 per cent. 
The one to which he had referred had a rotating disk, and he thought 


PROCEEDINGS OF THE SOCIETY. 661 


the straight slide was to be preferred, as it could be pushed higher 
or lower in the body-tube until the best position was found. 

The President thought that so far as an amplifier was useful— 
and in many cases it was useful—the form which Mr. Mayall had 
exhibited was a good one. 


Mr. Conrad Beck exhibited and described a new form of Micro- 
scope lamp (supra, p. 628). 

The President thought that the lamp was most ingenious and 
satisfactory, and that many of the arrangements were such as would 
be of great utility to working microscopists. 

Messrs. Swift’s lamp, a cheaper form of the one shown at the 
March meeting, was also exhibited by Mr. J. Mayall, jun. 


Mr. F. F. Hazlewood’s note was read as toa human spermatozoon 
with two tails. 

Dr. Anthony confirmed the statement that the occurrence of this 
variation from the normal type was not unprecedented. 


Mr. J. Brennan's further communication on the Potato-blight 
Insect was read. 


Mr. Cheshire described an organism which he exhibited, and 
which was identified by the President as a Spirochete. 

The President said the specimen showed considerable variation in 
the length and number of the spirals. 


Mr. E. H. Griffith’s new form of turntable was exhibited and 
described by Mr. Crisp. 


Dr. Anthony read his paper “On Drawing Prisms,” and illus- 
trated the subject by numerous specimens of drawings of micro- 
scopic and other objects. 

The President said the subject of Dr. Anthony’s remarks was one 
of great practical importance to all who desired to make microscopical 
drawings correctly. He had used various forms himself, such as 
Wollaston’s, Zeiss’s, and Nachet’s, though he thought he might say 
that he inclined towards the Wollaston, with which he had made his 
drawings of the flagellum of Bacterium termo. Although at the 
time he did not know why, he had found it quite necessary to tilt 
the drawing table in the way Dr. Anthony had described. 

Mr. Crisp exhibited, in connection with Dr. Anthony’s remarks, 
an ingeniously contrived drawing rest, which had been sent some 
time ago by the Geneva Physical Company, and which he thought 
met the want which Dr. Anthony had felt. It was an adaptation of 
the principle of the one figured at p. 565 of vol. iii. (1883) of the 
Journal. 

The President said that when working he had a somewhat similar 


662 PROCEEDINGS OF THE SOCIETY. 


arrangement made with a tripod on which the instrument was placed. 
For drawing he had a small table at the level of the stage mounted 
on a swivel, so that it could be used at any angle. He never worked 
below the level of the stage. 

Mr. Michael said he had used the camera lucida a great deal in 
making drawings of all kinds, and his reason for rising was that it 
seemed to be taken for granted that Zeiss’s form of camera was not 
so good as others. So far as his own experience and work were con- 
cerned, he had found it to be about the best, and he must confess 
that he did not see the image of the brasswork as had been described. 
His plan was very simple, for he used a drawing-board propped up 
upon books, so that the board was practically a continuation of the 
stage of the Microscope. If he thought that the image was not true 
he put in a stage micrometer and drew the image of it, and if this 
was done in two directions and both drawings were alike he knew 
that the projection was correct. As to the difficulty of seeing the 
pencil, he found that this varied very much with different persons, 
and that when he could not see it, others could do so with perfect 
distinctness. He liked to work with two lights and to have the light 
on the drawing-board much brighter than that in the Microscope; 
but on the other hand he found there were many persons who under 
these conditions would find that the image of the pencil overpowered 
the light from the object. He certainly thought the Zeiss form the 
best for ordinary mounted objects and for all such as were not 
mounted in fluid, whilst if it was desired to draw an object mounted 
in fiuid there was nothing better for the purpose than the Nachet 
form. The camera lucida, it should always be remembered, was an 
instrument for drawing outlines rather than filling up details. 

Mr. Beck said that the difficulties arising in connection with the 
camera lucida had from time to time come pretty prominently before 
him. There were two central forms which might be taken as types; 
one of these was the neutral tint reflector, and the other was the 
Wollaston. The neutral tint glass inverted the image so that a 
drawing made by it of anything which had the heart on the right 
side would be drawn as if it was on the left side. The practical 
difficulty met with in the use of the Wollaston camera was not 
because the Microscope had to be used in a horizontal position, but 
because of the difficulty experienced by some persons of seeing the 
point of the pencil. This might arise from the fact that very 
frequently persons used a large amount of light so that the pupil of 
the eye was very much contracted. He thought nothing could be 
better than the old Wollaston form; he had never himself found any 
difficulty in using it, and in spite of all the new contrivances which 
had been brought out, a large number of persons still used it and 
preferred it. 

Mr. James Smith said that with regard to the difficulty which 
Mr. Beck had stated some people experienced in seeing the point of 
the pencil, the best plan was to cut a very fine point to the pencil, 
and then dip it into black ink, which would render it perfectly plain 
on the white paper. With regard to the adjustment of light, it would 


PROCEEDINGS OF THE SOCIETY. 663 


be found that when making drawings by daylight it was a good plan 
to illuminate the object by the light of a small lamp, and to let the 
ordinary daylight fall upon the paper. 


Mr. Dowdeswell’s paper ‘On some Appearances in the Blood of 
Vertebrated Animals with reference to the occurrence of Bacteria 
therein,” was read by him (supra, p. 525). 

Prof. Bell said that Dr. Timothy Lewis who had been making 
some observations in India opened a dog and removed its two kidneys ; 
one was placed directly into warm paraffin and left to cool, and the 
other was examined at once; the latter was found to contain no 
bacteria, but the one which had been put into the paraffin was found 
to be swarming with them. This fact had not been referred to by 
those who were at present examining into the nature of cholera 
germs, but he thought it contained a moral which applied to all forms 
of disease. 

Mr. Beck considered the question to be an extremely interesting 
one. If what the Secretary had said—that the bacteria were the 
result and not the cause of the disease—was well founded, the same 
might apply to other diseases. 

The President thought that it was not Mr. Dowdeswell’s intention 
to say that there were disintegrated corpuscles, but that there were 
pseudo-bacteria. In the case of splenic fever the specific forms had 
been seen, and it had been not only proved that when introduced into 
the system they would give rise to the disease, but that when they 
had been filtered out the disease could not be so communicated, so 
that it was clear in this case that the bacteria were the absolute cause 
and not the result of the disease. 

Dr. Anthony and the President further discussed the paper. 


Mr. Oxley’s paper “On Protospongia pedicellata, 2 New Com- 
pound Infusorian,” was read by Prof. Bell (supra, p. 530). 


Mr. C. D. Ahrens’ paper “On a New Form of Polarizing Prism ” 
(supra, p. 533) was, owing to the lateness of the hour, taken as read, 
Mr. Ahrens explaining briefly the principle of his arrangement by 
means of a black-board diagram. 


The President said that at the last meeting of the Society it was 
mentioned that the American Society of Microscopists would hold 
their meeting at Rochester, N.Y., in August next, and he had been 
appointed, in connection with Mr. Glaisher and Mr. Bennett, to 
attend as representatives of the Society. Since then the American 
Association for the Advancement of Science had invited the Society 
to the meeting to be held at Philadelphia, and it had been proposed 
that the same gentlemen should attend that meeting also on behalf 
of the Society. 

This proposal was approved unanimously, 


664 PROCEEDINGS OF THE SOCIETY. 


Prof. Bell mentioned that the Victoria University of Canada 
had intimated their intention of conferring an honorary LL.D. 
degree upon their President during his visit to Canada, and he con- 
gratulated him on behalf of the Fellows on the honour thus proposed 
to be conferred. 


The following Instruments, Objects, &c., were exhibited :— 

Mr. Ahrens :—New Polarizing Prisms. 

Dr. Anthony :—Prisms and drawings illustrating his paper. 

Mr. C. Beck :—Microscope Lamp. 

Mr. Cheshire :—Spirochete. 

Mr. Crisp :—(1) Zenger’s Endomersion Objective; (2) Objective 
by Nobert, with curious form of correcting adjustment. 

Mr. £. H. Griffith :—Turntable. 

Mr. J. Mayall, jun. :—Microscope with sliding amplifiers. 

Mr. Piffard :—New Slide. 

Dr. Wallich :—Condenser. 


New Fellows:—The following were elected Ordinary Fellows :— 
Messrs. T. Breeds, Arthur EH. Davis, Ph.D., Robert Harwood, and 
James West; and Mrs. Catherine Crisp, the Hon. Mrs. Peek, and 
Mrs, Anne Wilson. 


a5 The Journal is issued on the second Wednesday of 
es February, April, June, August, October, and December. 


J ~@ 
Ser. ITI. To Non-Fellows, YQ 


Vol. IV. Part 5. OCTOBER, 1884. | Price 5s. 


Up 


JOURNAL 


OF THE 


ROYAL 
MICROSCOPICAL SOCIETY: 


CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, 


AND A SUMMARY OF CURRENT RESEARCHES RELATING TO 


ZOoOoLoGeyTYT AND BOTAN YW 
(principally Invertebrata and Cryptogamia), 
MICROSCOPY, Sc. 


Edited by 


FRANK CRISP, LL.B., B.A., 
One of the Secretaries of the Society 
and a Vice-President and Treasurer of the Linnean Society of Londow ; 
WITH THE ASSISTANCE OF THE PuBLIcATION COMMITTEE AND 
A. W. BENNETT, M.A., B.Sc., F. JEFFREY BELL, M.A., 
Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College, 
8. O. RIDLEY, M.A., of the British Museum, JOHN MAYALL, Joy., 
anpD FRANK E. BEDDARD, M.A., 
FELLOWS OF THE SOCIETY, 


if 
- 

“ 
¥ 
a . 
4 
7 

‘ 


WILLIAMS & NORGATE, 


LONDON AND EDINBURGH. bu(a) 
Goh, 


mse At 
= BY WM, CLOWES AND SONS, LIMITEN,] [STAMFORD STREET AND CHARING CROSS. 


CONTENTS. 


——eo7g,00——_—> 
TRANSACTIONS OF THE Soorety— Tse 
XVL—RESEARCHES ON THE STRUCTURE OF THE Caines OF 

Diatoms (continued). By Dr. J. H. L. oe ie X. 

and XI. and Fig. 119)... 


XVII. —On Drawine Prisms. By J. ‘AndlOny. MD. Cantal 


FROP., F-RMS. (Figs. 120-22)... 


PAGE 
665 


. 696 


Summary oF CurRRENT RESEARCHES RELATING TO ZOOLOGY ANR 


Borany (PRINCIPALLY INVERTEBRATA AND Cryprogamia), Micro- 
soopy, é&c., INCLUDING ORIGINAL Communications From FenLows 


AND OTHERS .. oe oy os se oe ae ee oe oe oe 
A Zoouocy. 
-Embryology of the Sheep BN geist Babe eet ot sary be aa ee eee 
Development of. the Generate Organs Tres emer ese 
Spermatogenesis .. .- sin coe! Rowe power ee eal te ol a 
Factors of Sexuality . NE ne ign ree can er eee 


Rudimentary Placenta ‘in Birds .. ae etea eal ema 
Permanence of larval conditions in Amphibia Praia reer iN iia 
Embryo Fishes .. + SSE EC AUER TTR I L. 
Development of Viviparous Minipod ce Pe ee a 
Formation of and Reactions of Nuclet .. 21 0. ee ee een 


Indirect Nuclear Division .. ce 2 aaa ele monies 
$: Nucleus of the Auditory Bpitheliwm of B Batrachians Sa neereh Saas eae 
Epidermis of the Chick .. Preanoriienn ee oye ten 
Scales, Feathers, and Hairs Spee Tate ahs ee 5 


Locomotion of Animals over smooth Vertical Surfaces Feigvand & ude Someta 
Zoology of the Voyage of the‘ Alert? 1. su ee oan we te 


Origin of Fresh-water Faune .. 1 s+ ee ae oe ae ne ae 


Pelagic Fauna of Fresh-water Lakes - cr 
Lowest and Smallest Forms of eae as revealed by ‘the modern Microscope .. . 
Intelligence in the Lowest Animals .. 21 oe se we vin aU eR anSe 
New Type of Mollusc... .. ey 


Taking-in of Water in relation to the Vascular System of Mollusca. 
Eyes and other Sense-organs in the Shells of Chitonidz Se uae ee 
Renal Organs of Embryos of Helix. .. se an ne oe we 
Nervous System of Parmophorus australis .. .. 2 + ; 


Organization of Haliotis. ..  . Gee pede eats vonte yon he eee aes 
Absorption of the Shell in Auriculide —.. gu SiR, cat eles aan 
Development of the Digestive Tube of Dimacina si pee Cas en aaa 
Simple and Compound Ascidians .. .. eer! cae toe EE 
Digestion in Salpa 506 ice veer Br Gee ae Oe a ae ne 
Fresh-water Bryozoa .... LOC a tsces, Cia tay omar tee 


Supposed new species of Cristatella .. 2 URE 
New Type of Elastic Tissue, observed in the Dine of Eristalis.. . 
Submazillary of the Jaw of Mandibulate Insects ..  .. 1s ss os 
“Structure and Function of Legs of Insects .. Se | ae 
Organs of Attachment on the Tarsal Joints of Tnsects cs wk a eee 
Locomotion of Insects on Smooth Surfaces. .+ 6s ae oe ews 
Organs of Flight in the Hymenoptera +. 41 se eee tee 
Poison of Hymenoptera and its Secreting Organs .. 1 6. ae oe 
Development of Cerocoma Schreberi and Stenoria apicalis ye Gate ieee 
Dipterous Larve.. — «. eda Risto ik aces eae cba a ale are 
Larve of North American Lepidoptera .. Seek Rae tk eo aah eee 


Drinking Habitof a Moth.. .. + SG Atk ay eee 


Michael's British Oribatides MLSoeivuan Gewac C amis aera apne 
Stomach of Podophthalmate Crustacea .. 11 05 su an op we 
Significance of the Larval Skin in Decapoda... ... 2. «+ ee 
New or Rare Orustacea .« os se nee we we | os we 
New. Type of Hérudined cco oe = ae ee an an tae Sen as ee 
Structure of the Branchiz in Serpulacer .. Ue cae 
Structure and Development of rb ihiariaak Dendrocala RY Gales al ee 
Classification of the Rotifera .. .. wee Stew Foes CUR rem ERNE 
Constitution of Echinoderms ~.. (1. 06 5 oe \ oe te on tet 
PGi tgs vers ee Sak as SAU kes ts Seen os ORE eee ey 


(C8) 


_Suamany or Current ReskArouss, fea 8 A 


5, Anatomy of Lareat SOME Bra sip 8 SESE ae ESE RET Ue heals TE 
_. Notes-on Meduse... |... Giver cae) SGP bers pi pie WR a ee eke pec’ 2 heer MaleD 


" Revision of the Madreporaria SEtk atk Oe eee a ART pha ed oak hee OD 
: Bee ee es ee Baily eet a telat oye cat a eager sie 1 Oe 


Siliceous Spicules of Sponges Bora dn tity a as SE 
- Fresh-water Sponges and the Pollution of River-water Sei ak oes UE 
New Infusoyia IR PR oe eee Roepe cae Peery ten Patsy AAMC ner Ci ES |. 
” Pardsitic Peridinian .. Ss ial A ia aaa ae Laos Sat te hed is a Ee eae 
Observations, on Flagellata ... Fe SecA woud eo Web oet Male aan Saree ema e 
_ Geometry of Radiolaria SS wan /ig a ORE Deo hs EE Oty t Dare ig eo 
- Polythalamian from a Saline Pond . ig ne See) ell. Cal iain ete ea 


_ Nuclear Division in Actinospherium eichhornié. .. - ..  .. 495 goes er eee 
- Parasite of the Wall of the Intestine oe the Horse Joy) LER AE ah hs ete ee 
secant “ Fozoon” ie cae Meg as Le beet Raine aE 


- 


Borany. 
Continuity of Protoplasm .. 


Osmotic Poiter of Living ‘Protoplasm ey weit oe 
Structure of Pollen-grains SSP eae Oar ee aE eS 
' Seeds of Abrus prxcatorius .. re 
- Oe eiaparetiee Anatomy of Coty wiidons and i Enddepern ees 
~~ Underground Germination of Isopyrum thalictroides ..  .. 
' Stomata of Pandanacer .. 
~~ Changes in the Gland-cells of Dionza muscipula during Secretion 
__ Septal Glands of Monocotyledons °3.- 0 ae ae ne aa a 
~ Secretory System Of COmBOnl Be ea Geel eevee en ee en 
We * Chemical Constituents of Plants ©... 2. we ee 


phe “Structure of Leaves 2. 1. ee ee ee eee 
~ Transparent Dots in Digber hg ee 
- Seeretory System of the Root and Ren ee 


_ Anatomical Gtructure ofthe Root. og -8 8 5 ean ae a ae 
Growth of Roots’:. *.. ae ie ee 
‘ *" Growth in length of decapitated and uninjured Roots .. P 
roo « Geotropion and Hydrotropism of Hoots .. + s+ + 
j - Water-glands and Nectaries .. . sng. Sly tos 
~ Folds of Cellulose in the Epidermis of Pitala’ Siena ee 
~ Anatomical Structure of Cork-woods alae take Po nay ett maT 
- _ * Filiform Apparatus” in Viscum cle 
~~ Ae¢tion of Heat upon Vegetation ie 
_- \ Relation of Heat to the Sexes of Floivers 3) ‘3: RA 
Influence of Light on the Structine of the Leaves of Altium ursinum 
ee SE sr, aect of Light and Shade on Fea ca PB ee eae a 
- .. ~ Movement of Water in Plants .... Rae cas aie 
% fs: Movement of Water in the Wood 2. ek a as 


~ Measurement of Transpiration .. Sort esa oak ie 
ple | Betaiaton of Ozone by Flowering Plants Deity MORTARS ake vata 
* Acids in the Cell-Sap’.. Eo iw goog Se 


eS Bt Colouring Substance from Choro hyth ct bens tame ee 
7 a eotalline Chlorop phy mee o- ea “ oe a Py *e 7 
Gh stals and Crysta ee a : 


gta Ge On Gao iee 
Tit ie Cli te GaN Mag Faas a core 
CE PUIG co hee ig ise, een knee Salou. Wane 


ie AGORA PIQUA EE oi foe NG 8 oct) oak np ones > we: os pa 
t: _, Bish caught by. Utricularia ye Wen Pye , #6 ae - ‘we - 
Yims Oe apie ‘Cryptogams. 1. 6. oe we ae oe ge 


oa |) Fartltsation oe o. os oe or wa iee dein 
7 Male Misaadee of Moves s0 04S ee be 

ae. aquereus and Jarnes's Moses of North America... yids on oh tae 
Supposed ion and 9 al is Nitrogen by. Pungi oa Rowe 
Feet itic on Drosophila . a ety 


f 
> ” rd * ae 
“ aa fas 
ge 
e 


Fermentation as y 


. ae Se ge a a 
- Somany OF Oiihanr REsgARCHES, ‘ke ON ne: 


Bacillus of Cholera sees .\%p- Se bs ee he ow aes 
3 bies ee so ‘eo as ec. ee ot = 6o - oe on. 
Etiology of Tuberculosis. - «. gen ee tee a eee 
Bacteria and Minute Alge on Paper Money .. CRE es 
Grove’s SEB of the Bacteria and Yeast Fungi? sek ue ee 
Protochytrium Spirogyrz, a new Myxomycete (2) 4. +1 oa 
Substratum of Lich ens eo «swe ae eo be oe oo | ee 
Huymenolichenes ose. 3s Aies ee ee wes ers bess ea bs 
Fresh-water Phzospore ve es oy oe sh 60 eek 


Nostoc ees oe ee wae 1 se ee = oe Sere ee wé 
New Chromophyton Se Cader sey See ee 
Wolle’s Desmids of the United Bikes: San oe 


New Diatoms—Diatoms from Stomachs of Seawe Oysters poche ae 
Structure of Diatoms eo ee eo oe eo : eo ee oe eal oo ise 


Microsoory. 


Albertott#’s Micrometer Microscope (Fig. 123) - .. Soar cae 
Baumann’s Callipers with Movable AONE, and Fixed Micrometer Re 


(Figs. 124 and 125)_ & We ieee © Saale 

: Geneva Co.'s Microscope Calipers (Fig. 126) Sige ood Jae nile 

fe ee ne Grifith’s Club Microscope... oe ee eo “ee : ‘eon ee ee 
eS ' Nachet’s Class Microscope (Fig. 127) eee ey 

NG Pee Nachet’s Microscope with Large Field .. Ae pee 

PEE Ain Stephenson's Aquarium Witipomtope (Fig. 28) a " eer 

Swift and Son’s Oxyhydrogen Microscope (Fig. 129) Sai te 

Nelson's Hydrostatic Fine Adjustment (Pigs. 180-182) | EN a 


ee he Griffith's Nose-piece (Fig. 133).. —.. eye, 
tee a Sele Hyé-piece with additional Lene “Ge a ‘Condenser Slee ea 
Pa DiGlOmekOOPe™. ey. ek Sok oul 9a Dee ees ae, Came 
ae Flardy's Collecting Bottle 552 ose <0 ican 2G b0k- specced en ea 
es Eye-piece Amplification .. ein hare aa nes Suen 
ee Illumination and Focusing in Photo-Micrography Seen 
~~ Mitchell's Focusing Glass for Photo-Micrography .» ov «» ° « 
-. Photo-Micrography. in Legal Cases (Fig. 134) se ee ne oe 
~ American Society of Microsopista +» 11 +e +e oe nh ae oe 
: Health Hxhibition se we. ee i apes | eo ee ee ee et” ° 
Killing Infusoria bo oo o> oe ee eo oe oe oe Ae 
“Perchloride of Iron .. Sas 
Mounting of Foraminifera—New Slide for Opaque Objects 
ere lin as a Reagent for Pec satis Non-suberized  Celtutoe 
é! ‘NES os ve eo oe PO ee, oo be lee oo ve 6 
Canarine for Staining .. 2h ate 
Cultivation of Bacteria upon the Slide Giga. "135 aad re Testes 
Staining of Schizomycetes in Sections and Dry Preparations .. 
Staining Fluid for Sections of Seid eae aes VES aa aeeed 
Methods. of Imbedding (Figs. 187 and 138) .. 0 4. se te 
_ Hoffmann’s Imbedding Apparatus (Fig. 139) eee Swe cece hoee tee 
’ Celloidin for Imbedding .. iSeeamare pha toey wae p 
~ Reichert's Microtomes (Figs. 140 and 141) Bias inter. aspen oul aeas 
_ Decker’s Section-smoother (Fig. 142 2 a ee ee 
Griffith's 3 Turntable (Fig. 143) oo” ee oe oo ge , ie z : 6, aS 
Reversible Mounts a | Peritersl 5 oe. _@e eo ee eo ee 
 Hinman’s Device for Mounting .. Bae es tag yk PRLS, Ps eet 
Preparing Schultze’s Solution 5. a pe) ov ae jae ee we 
2 * Styraz and Tiquidambar . es ee Re pe ae 5 a0" & RS 0 oe Me oe. 
i , Preparing Shellac Cement .. ee ee oe a op HES ° « : Ye Sate ae 
: ae Coating Diatoms with Silver oo) ee kgs Saar y hk eee oe oe nn pies 
Rest ; Lyon's Mailing Case. pee 
~~ Action of Reagents tn ihe aueortindantton of Vegetable Fibres eS 
" Reagents for Tanning in Vegetable Cells... .. se ae ae es 
Microscopical Examination of Chestnut-meal .. ee ae ae 
Microscopical Investigation of Dyed Cotton. Hubris Se terme 
- Microscopical Examination of Water for Organic Tmpurities — 
Changing the Water in Aquaria contaming Microscopical Organism 
> pees Micro-Chenical Test for Sodium Spee TE Ores ee iS 
MRO Micro-Chemical. Reaction of Solanine eens ee eae 
: Beas Size ae. oe oe ee oe on. ae op ee ae es as 3 wp 


eee 


“ROYAL MICROSCOPICAL SOCIETY. 


COUNCIL. 


ELECTED 138th FEBRUARY, 1884. 


PRESIDENT. 
Rev. W. H. Datiinerr, F.RS. 


VICE-PRESIDENTS. 
Joun Antuony, Esq., M.D., F-R.C.P.L. 
Pror. P. Martm Duncan, M.B.; F.R.S: 
Jawes Grarsuer, Esq. F.RS., FRAS. 
ee. STEWART, Esq., M.B.CS., F.LS. 


TREASURER; 
-Lrovet §. Bratz, Esq., M.B, F.RCP., FBS. 


SECRETARIES. § 
os Crisp, Esq., LLB., B.A. V.P. & Treas. LS. 
Pror. F. Jerrrey Bex, M.A., B.Z8. 


Twelve other MEMBERS of COUNCIL. 
Aurrep Wiur1am Bennett, Esq., M.A,, B.Sc., FLS. 
Rosert Brarrawarrs, Esq., M.D., M.R.C.S., F.LS, 
_G. F. Dowprswett, Esq.,. M.A. 

«J, Wmram Groves, Esq. 

- ‘Sonn E. Incren, Esq. 

 Joux Marrnews, Esq., M.D. 

Joun Mayatn, Esq., Jun. 

— Ausrrt D, Micuan, Esq., F.LS. 

~- -Jonx Muzan, Esq., L.R.C.P.Edin., F.LS, 

~ Wrsaw Muar Onp, Esq, MD. F.R.CP. 


Unsan Prrronarp, Esq., M.D. AN: : : fe es A ee 
Wuuam Tuomas Surrorx, Esq. es ame od 
LIBRARIAN and ASSISTANT SECRETARY. oes Tae 


I. Numerical Aperture Table. 

‘The “ ApertuRE”’ of an optical instrument indicates its greater or less capacity for receiving rays from 
transmitting them to the image, and the aperture of a Microscope objective is. therefore determine s 
between its focal length and thé'diameter of the emergent pencil at the plane of its emergence—that is, 
diameter of.a.single-lens objective or of the back lens of a compound objective. pt oes iat oe 

This ratio is expressed for all media and in all cases by 7 sin wu, n being the Yefractive index of the medium and @ 
semi-angle of aperture. ‘The value of m sin w for any particular case is the ‘*mumerical aperture” of the d 


Diameters of the _ Angle of Aperture (=2 4). | —‘Dheoretical |= 
* Back Lenses of various e : - = Tilumi- |: Resolving’ 
Dry and Immersion Numerical} , > Water- | Homogeneous-) nating Power, in 


Aperture. |_| Dry ; : 3 op 
AB eee Immersion| Immersion \| Power. | Lines te an Inch;} 
(nm sin w= a.) | Objectives. | Opicctives.| Objectives, | (a3.) | (=0°5269p | 
(7 =1.) a5 
AD aay Zo: (bs =33.)\. Gul 1°52.) he. ves == linediny 


Objectives of the same 
Power @ in.) — 
from 0°50 to 1°52 N A. 


| 


ae 98 180° 0’ 2°310 2b tO, Ved, 
| wef 161° 23% | 2-250] 444,600 
oe ey 1539-39" | 2°190 | > 142,672. 
Pere eee vide vee yaa Cre 
oe | Se Sh 422 40% | 22 074 ees ae 
ss 188% 19" 2-016)" 136,888 

= ye - | 1842 10" |1-960.)° 784,960 


COCO OT 


53 ne 130° 26" | 1-904]: 138,032. 
ae s | 126° 57" | 1-850] -. 13%, 104 
as -} 23° 40". | 1-796! 1292176 


w. 1 180° 0’) 122° 67 |1-770| — 128,972 
s 165° 56"| 120° 38 | 1-742) 127,248 
ve | 155° 88"|- 117° 84’ }1-690; 125,320 © 
> ye > (1480-28) 114° 44” 17-638 3, 

as 142° 39'| 111° 59’ | 1588} 121, 


.. _ /187° 86’) 109° 207 | 1-538 
w | 1880 4’| “106° 45’ | 1-488} 
Ny |198° 55") 104° 15" 1 +440 | 
yo -- 1125°-8'| 101° 50’ | 1-392 
«© | 121° 26") 99° 99" 41°46] 412 
%; 1°300| 1 


* 


¢ 


HAHAHA ADD AOIIIIIOMDDHDDODODDOODOOCOH EHH UYNYWNWHM 


CVUBDAROVKADOWKHG DOV KABDOWHADSOWKADOVHAVDOWRADOWVWBADOWRADOW 
2 


29900999999 90900909 000 COCR PEER HEHEHE HH BHM HME Hii 


_ -Eximpre:—The apertures of four objectives, two of which are dry, one water-immer 

would be compared on the angular aperture view as follows:—106° (air), 157° (am), 
‘Their actual apertures are, however,as §; Re 300% tx) 98 

"numerical apertures. aie get ea aD ge 


(1.) Lrygab. 


' Micromillimetres, §c., into Inches, ge. 


Conversion of British and Metric Measures, 


Inches, §c., into 


; ing Micromillimetres, 
a B ins, | mm. ins. | mm, . §¢, 
ni nets, / 1 -000039; 1 “039370 | 51 2:007892| ins,  —p 
Besacties. 2 -000079| 2 -078741| 52 2°047262 | . 2 - 1-015991 
Sea 8 000118; 38 ‘118111; 58 2-086633 { (2. 1:269989 
2 4 +000157| 4 "157482 | 54 2:126003 | "i" 1-693318 
. 5 -000197| 5 "196852 | 55 2°165374 | 7°" 9-539977 
aT - ~ 6 -000236| 6 -236223 | 56 2°204744 | 7°29 9.899197 
| 7 -000276| 7 -275593 | 57 _ 2°244115 | a 8-174972 
a 8 -000315; 8 *314963 | 58 2°283485 | 72, 3°628539 
3 9 -000354| 9 -354334 | 59 2°322855 | 11 4:933005 
" ~4) 10. -000394 | 10 (1em.) +393704| 60 (6cm.) 2°362226] ~1 5§-079954 . 
i -000483 | 11 -433075 | 61 2°401596 | soon 67349943 
| “000472 | 12 -472445 | 62 2:440967 | sop _87466591 
x -000512 | 13 “511816 | 63 2°480337 | sooo 12°699886 ~ 
+ ; 1 . ; 
=| | -000551 | 14 651186 | 64 2°519708 | ross 20°399772 
BI | 000591 | 15 *§90556 | 65 2-559078 : 098002". 
| “000630 | 16 -629927 | 66 2598449 | Fed ee 
* -000669'| 17 -669297 | 87 2°637819| soo * pete 
>| leg! -000709 | 18 -708668 | 68 2-677189 |. oe (etaee 
5 : “000748 | 19 “748038 | 69 2°716560 | 380° 
= 000787 |. 20 (2em.) °787409| 7O(7 em.) 2°755930 ae seat 
a -000827:| ‘21 “s26779) 71 Bie ato 108349 
=| Oe ele es +000866 |. 22 - *866150 Le *OT2574 
) ~000906 | 28 -905520| 73 2°874042| 23°". .ogagee | 
A | eee eee eee| eae 
a 000984 | 25 : : : *126999. 
- -001024 | 26 1-023631 |. 76 2°992153| 22°  .769382 | 
= 001063 | 27 1-063002 | 77 87031523; [2° «953998 
-001102 | 28 1°102372 | 78 8°070894 Py... 7507995. 
| % “001142 | 29 1°141743 | '79 8:110264| 2° 4-015991 | 
5 i “001181 | 80 Bem.) 1181113} 80 Bem.) 37149635} 
a} -901220| 31 1220183 | 81 3-189005| 
i} |. |) + 82. -001260 | 32- 1°259854 | 82 3228375 | Ts 
mlb *001299 | 33 1:299224) 83 3°267746 | as 
z 001339 | 34 1°338595 |. 84. 3°307116| a” 27939977 
a *001378 | 35 1:377965 | 85 3°346487) = 
| -001417 | 36 1:417336 | 86 3°885857|- @ 
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JOURNAL 


OF THE 


ROYAL MICROSCOPICAL SOCIETY. 


OCTOBER 1884. 


TRANSACTIONS OF THE SOCIETY. 


XVI.— Researches on the Structure of the Cell-walls of Diatoms.* 
( Continued.) 


By Dr. J. H. L. Fréaer. 
at 
(Read 12th December, 1883.) 
Puates IX., X., anp XI. 


5. Triceratiwn. 


Tue old attempts to explain the sculpture of this group may be 
assed over, also Prof. A. Weiss’s work of 1871 (28), since we 

ve a very good paper by O. Miiller on Tvriceratium favus Ehrenb. 
(15), which elucidates the entire sculpture of the valve in a most 
satisfactory manner. I might therefore omit my investigation of 
T. favus, the only species I examined, the more so as I have 
generally only to confirm Miiller’s results. As, however, Tricera- 
tium is taken as the type for diatom sculpture generally, and 
because in minor points I arrived at somewhat different results, I 
prefer not to suppress my investigations which were made from 
sections (serial preparations) and casts. The material was presented 
to me by Herr Moller, of Wedel. 

The production of sections perpendicular to the surface of the 
membrane is a comparatively easy task. The large triangle can be 
readily seen in the gum, and the knife guided accordingly. Series 
of 15-20 sections can be made without difficulty. 

We have, as Miiller correctly describes, a thin basal membrane 
adjoining the cell-lumen, and apparently quite smooth. © On the 
outer surface is a system of ordinary network mostly representing 
hexagonal spaces, which are vertical chamber-walls. Above, these 
lines extend to almost horizontal walls, leaving, however, for each 
of these chambers a large round central opening. ach of the 

* The original paper is written in German, and has been translated by Mr, 
‘J. Mayall, jun. 
Ser, 2.—Vor. 1V. 2¥ 


666 Transactions of the Society. 


hexagonal cells observed in the surface view is therefore « chamber 
in the shape of an hexagonal prism; only the base of the same, 
the outer surface, is not complete, but has the well-known and 
often-described circular opening. On the vertical walls—namely, 
the side faces of the prisms—in the corners of every third chamber 
isa spine. If the thicknesses of these fine membranes are to be 
measured, very choice sections must be taken. The basal mem- 
brane has a very fine sculpture as illustrated by Weiss, but much 
better and more accurately given by Miller. It consists of a 
system of fine dots, radiating in lines from the central space of the 
entire valve, and of which 60-80 are contained in an hexagonal 
cell. Only on the finest sections with the highest power one 
catches a glimpse of these points. I cannot say that the line would 
thus be seen distinctly beaded ; and equally invisible are the points 
adhering at the inner side only of the basal membrane, as Miller 
represents it in transverse section (his fig. 11). Possibly these are 
also chamber-like cavities, as with Plewrosigma. The definition 
will be very difficult, but possibly casts will help us hereafter. 

We have still to consider the margin of the valve and the three 
horn-like protuberances. Miiller has spoken of these explicitly, but 
I find some variations. With regard to configuration of the margin, 
Miller gives correctly (his fig. 9) the view of the surface of the 
marginal line. The transverse section (his fig. 11 d) represents 
this line too much bent inwards. I have therefore given a diagram, 
plate IX. fig. 21, of one of my transverse sections. The line is nearly 
vertical to the membrane surface and is slightly broader at the top, 
not pointed. The three protuberances at the three corners of the 
triangle have been correctly rendered by Miller ; but everybody who 
has not seen them in sections will find it difficult to realize them 
in his figs. 6 and 7, because they exhibit too much of other detail 
and shadow. For this reason I give the diagram of a true vertical 
section of such a protuberance, fig. 22. According to Miiller, 
these protuberances might possibly be open at the point, for which 
I have not found the slightest justification. Nor is his cited ex- 
ample of Hupodiseus a proof, in my estimation, because I see the 
points in this group also closed. 

The method of collodion casts confirms in general the results 
obtained by the section method. The collodion enters through the 
outer larger opening into the chamber, and leaves on the surface of 
the dry cast a somewhat round mass which has very little likeness 
to the beautiful regular prism of the chamber. On closer examina- 
tion one distinguishes these spines in the cast as distinct depres- 
sions in the corners between the masses. The cast of the inner 
side of a valve is perfectly smooth. I could not succeed in obtaining 
a cast of the delicate porous structure, either because it does not 
exist or because the collodion used showed reticulation in hardening. 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 667 


6. Coscinodiscus. 


Of this species I have examined four varieties. I collected the 
material myself on the Norwegian coast, and another portion was 
from the ‘ Pomerania’ expedition (9). 

§ 1. Coscinodiscus radiatus Khrenb.—This species gave the 
best results, because the chambers are of considerable size, and I 
had a sufficient quantity of them. Among the specimens obtained 
with the knife one is especially interesting, because it was ob- 
tained during fission. This is represented in fig. 31. I photo- 
graphed a particularly successful section as a type-image. This 
section is very good, but for the study of the sculpture a little too 
thick ; for this reason I have delineated in fig. 23 the marginal 
portion of an adjoining fine section under very high magnification. 
From both images the sculpture of this species may be deduced as 
follows :—The general form of C. radiatus is a very thin disk like 
a coin; both faces are circular and display the pretty delicate 
areole. Vertical sections through the disk give everywhere the 
same image, the central one included. The cell-wall of these disks 
consists of a very thin basal membrane, having on the outside 
very delicate but prominent network. This network is enlarged 
and thickened at the end, and so much enlarged that the lines 
almost coalesce. In inferior sections one sees a continuous outline, 
which is divided from the inner membrane by bars, but in very 
good sections the lines have the shape of a T. In consequence 
the network forms prismatic chambers, mostly hexagonal, but also 
five-sided and four-sided, which without doubt must have an open- 
ing from the outside, even if it be very small. In the surface view 
I did not observe this opening until after my attention had been 
drawn to it by the sections. It is seen with balsamed prepara- 
tions like a small nodule, having 1/4 to 1/3 of the diameter of an 
areola, and in superficial examination it may easily be mistaken 
for the focal image of a chamber. To decide this point search 
must be made above the acute portion of the chamber-walls. 
The large number I examined of good sections which all agree 
when thin enough, and show no continuous outline, prove defi- 
nitely the existence of a small opening. The opening, in proportion 
to the size of the chamber, is smaller than the circular opening 
of the Triceratium chamber, as may be seen from the diameter 
of the chamber-walls, which have a somewhat different shape from 
Triceratium. Otherwise they are both very similar, but Coseino- 
discus has no spines ; the outer surface is therefore smooth. The 
height of the chamber is equal to its breadth (8-3-2). To- 
wards the edge of the disk both dimensions decrease. The girdle- 
band is seen in most of the sections; it is without sculpture. 
Regarding its connection with the two inner newly formed cell- 

me 


668 Transactions of the Soctety. 


wails several results were obtained with the sections. These 
two new disks have the same sculpture as the two of the outer 
valves, except that all outlines are much finer, and the chambers 
are also not exactly of the same definite height. One observes that 
the chamber-walls in the two young disks sometimes touch each 
other, sometimes not. The manner in which all these parts are 
connected with one another is very peculiar. I must here refer 
to what I say further on about Achnanthes. With Coscinodiscus 
there is no doubt that at least the one of the two newly formed 
cells is completely closed outwards. The basal membrane of the 
one outer valve goes continuously in equidistant curves into the 
basal membrane of the corresponding inner valve; at the bend 
a few delicate lines are seen which are the sections of the walls of 
the considerably reduced marginal chambers. Out of this portion 
the new girdle-band must be developed, as hitherto it has not been 
detected. One observes in the other newly formed cell (the lower 
one in the fig.) existing in all central sections a break, which the 
membrane of the new valve makes at the bend, and this gives the 
appearance as if the basal membrane of the old valve was con- 
tinued here directly in the inclosed girdle-band, which is probably 
the case; but one also observes here a break. Nevertheless I 
believe that this second cell is closed at the bend of the membrane, 
a conviction to be gained only by very careful study of the entire 
section series. Future investigators who will work with patience 
have an inexhaustible field before them; they will have to turn 
their attention specially to the gradual development of the chamber- 
walls and determine whether, for example, as Miiller indicates for 
Triceratium, network arises from a basal membrane at first 
smooth, or whether it is more probable that at first hollows are 
developed in the membrane which afterwards become chambers 
open at the top. It is interesting to see im this fission specimen 
how, during the process of division, the lumen of both cells was 
reduced almost to nothing, and very nearly the entire inner space 
of the former mother-cell was filled up with the substance of the 
two new walls. A coalescing of the two disks during the imbed- 
ding in gum cannot be entertained, inasmuch as they would show 
cracks at the edge, as old valves are unusually brittle. If we com- 
pare with this an ordinary undivided specimen, from one of which 
T have given a nearly median section out of the marginal portion, 
fig. 24, the difference is at once apparent. In other respects such 
a section displays very little variation from the above representa- 
tion. The first section through the same specimen, which shows 
the girdle-band of the surface and the minute chambers in the 
convex edge, is given in fig. 25. I could not obtain collodion 
casts of any service, nor could I succeed in fixing permanently 
colouring matters in the spaces of the chambers. If the latter 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 669 


could be accomplished with not wholly soluble but only suspended 
colours a further clear proof would be furnished of the existence 
of the openings of the chambers. Fossil specimens of Coscino- 
discus radiatus from marl slate from Oran, for which I have to 
thank Prof. Dippel, appear in their section-images quite in harmony 
with the above. As a matter of course here is no longer cellulose, 
and the valves and the girdle-bands are isolated. In the surface- 
image the opening to the chamber is a little larger than with the 
other specimens, which may be attributed to the loss of the cellulose. 
Putting the outer surface (for instance, line 1, fig. 23) under a 
high power we see these openings as delineated in fig. 26. By 
slightly raising the slide so that line 2 is seen, the inner ring dis- 
appears and distinct chamber-walls are seen, fig. 27. One esti- 
mates the thickness of these walls in the surface-image too high, a 
circumstance connected either with the magnification of the outer 
marginal thickening of these walls, or which must be explained by 
the reflection of the light from the walls.* 

In a few specimens, not far from the edge, I observe unusually 
large chamber-walls, fig. 28; the cavity is apparently quite 
spherical, and only at some distance off does it take the prismatic 
form. It seems to me quite unimaginable that the membrane should 
have raised itself as an annular wall until quite above or nearly 
so, and then have closed itself again over such a cavity (the pointed 
shaped opening seems really sometimes to be wanting altogether) ; 
and for this second reason in support of my former conjecture— 
according to which the cavities develop and enlarge themselves in 
the substance of the walls, and in this case open by the resorption 
of the girdle—I give preference to my explanation rather than to 
Miller’s. 

§ 2. C. Oculus iridis Ehrenb.—The works of Slack, Stephen- 
son, and Morehouse relating to this species (25, 26, and 13), I know 
only through Just’s ‘Jahresbericht.’ According to Pfitzer’s refer- 
ence, Stephenson describes an outer layer of deep hexagonal cells 
which are one anda half times as deep as broad, and which, judging 
from the positive images which they give of outer objects, are either 
open on both sides or closed by nearly plane membranes. The 
latter becomes more probable through the appearance of small 
depressions in the base of the cells, the edge of which is undulated. 
The inner layer Stephenson describes as a thin hexagonal areola 


* On this subject compare my work on Pleurosigma, p. 507, where the reflee- 
tion appearances within vertical chamber walls are fully discussed. With a 
stage having an opening covered by a glass plate which is slightly tilted 
these experiments can be controlled. Since outwards of the edge-line of a wall 
black always appears first and white within, it becomes evident that with small 
dimensions an apparent thickening of such vertical membranes must always 
reg because the eye naturally takes the middle of the black line as the 
imit. 


670 Transactions of the Society. 


plate having a spherical opening in the centre of each hexagon. 
Slack asserts he has seen real depressions and a real projecting 
network, both composed of small spherules. Morehouse sees duplex 
valves, the inner of which has spherical openings, the edges 
representing the thickest parts of the valve; the hexagonal net- 
work of the outer valve lies in the depressions between those edges. 
Across the mesh of the network extends a thin siliceous film with 
most delicate anastomosing network, having its weakest point in 
the centre. All sorts of things may be observed on this object if 
one remains satisfied with a mere examination of the surface. The 
nearest approach to the real state of affairs was made in 1880 by 
Prinz (21). His figs. 7 and 8 represent tolerably well the vertical 
chamber-walls, although by the method applied (the experiments 
were made with thin rock sections) the real details would be difficult 
to make out. This species viewed on the surface is to be dis- 
tinguished by the large areola in the centre of the disk; the section 
shows that the entire cell has no longer the form of a coin, but, in 
consequence of the slight curving of the disk, is like a bi-convex 
lens. The areole are slightly smaller than those of C. radiatus. 
My somewhat numerous sections through one specimen are very 
similar to those of C. radiatus, but I find nowhere a definite clue 
for the existence of an outer opening. In fig. 29 a small portion 
of a vertical section is given to the right, as observed with most of 
the sections; on the left are seen small portions in the edge of fine 
slightly injured sections. Here I am in doubt whether the 
T-shaped figures may not be produced by the splitting of the very 
fine outer membranes which are in the girdle; if everything in the 
gum is uninjured one sees the membrane extending evenly across 
the supports without indication of holes. It is curious that with 
this species very often an air-bubble remains behind in the chambers 
which hardly ever occurs with C. radiatus and Pinnularia, and 
this might suggest that the fluid gum does not enter through 
openings but in the more difficult endosmotic process. It is 
unnecessary to deal more in detail with the statements of Stephen- 
son and Slack. The former has apparently arrived at his view 
through examining a specimen in process of fission. 

§ 3. C. centralis Ehrenb.—This is a very large species, of 
1/3 mm. in diameter, strongly convex, having in the centre a few 
large areole. I have before me a number of sections through a 
valve which had unusually coarse markings, thus differing but 
slightly from C. radiatus. Fig. 30 is a portion of one of the best 
sections, and shows the chambers with the T-shaped sections of the 
walls, suggesting arches; the surface view is like C. radiatus. 
Here also no opening can be detected in the finest edge-portions, 
therefore I believe I am accurate in stating that this species has 
completely closed chambers. One must not be led away by the 


Lhe Structure of Diatoms. By Dr. J. H. L. Fligel. 671 


marginal shadows which give the above strongly thickened T lines. 
A close examination confirms the existence of a very fine line 
between them. Hence we have here two distinct membranes con- 
nected by a system of mesh-like walls. The walls commence at the 
inner membrane very thin, and gradually become thicker as they 
approach the outer membrane, so that they appear wedge-like in 
the section. Similarly the adhesion point at the outer membrane 
is thickened, and this thickening gradually diminishes over the 
centre of the chamber. ‘he outer surface of the outer membrane 
is uncommonly even, so much so, that in a dry condition the valve 
reflects light as strongly as a mirror. This fact alone cannot be 
reconciled with the idea of openings (C. radiatus does not reflect 
as a mirror), anyhow the openings could not be estimated at more 
than 1/8 or 1/10 of the chamber diameter in order not to interfere 
with the smoothness of the membrane. Collodion casts would be 
very desirable in the investigation of this species. The dots of the 
areole in the surface view, formerly described and figured by me 
(9, p. 86, fig. 6), cannot be seen in the sections. 

4. C. concinnus W. Smith.—This species is much larger and 
more delicately enveloped than the former, about 0°5 mm. in 
diameter and equally convex. The section of a valve of a not very 
large but very finely marked specimen, fig. 31, shows the familiar 
image of chambers closed on all sides, such as I demonstrated by 
my Pleurosigma investigations, except that with this Coscinodiseus 
they are considerably larger (about 1 yw). The valve reflects light 
strongly. For the surface view I refer to my former notices and 
figs. (9, p. 86, fig. 5). After the investigation of these four 
varieties I believe that in the species of Coscinodiseus we have before 
us the gradual transition from the Triceratium type to the Pleuro- 
sigma type, inasmuch as the small outer opening of the chamber 
which is still seen in a few varieties, totally disappears in others. 


7. Isthmia. 


It is not at all difficult to cut this giant amongst the diatoms, 
but it is very difficult to obtain sections of the requisite degree of 
fineness. The cell-wall is everywhere of unusual delicacy. After 
examining some forty-five sections I am enabled to give the follow- 
ing description of the cell-wall :— 

There is a difference between that portion of the frustule which 
corresponds to the valves, viz. the sloping ends of the rhomboidal 
cell, and the middle portion, which is to be regarded as the girdle- 
band and under which the division takes place. This difference is 
marked outwards by a strong expression of the areole in the end 
portions in contrast to the delicate markings of small cells in the 
girdle. With the sections one must always endeavour to determine 


672 Transactions of the Society. - 


to which part the portion belongs which is under examination. In 
order not to err on this point | have kept to the pointed ends in © 
the investigation of the valves, and which exhibit in the section 
comparatively very small rings. Photograph 19 illustrates a 
section through two frustules and through one connecting end 
being the isthmus proper. The small ring, without doubt the 
valve, shows on the inner side distinct projections, that is to say, 
wall-thicknesses apparently vanishing like network produce the 
cell-ficure in the surface view. The membrane at the non- 
thickened end, that is to say, at the lumen of the pseudo-cells, 
is of extreme thinness. The immediately preceding much finer 
section corroborates still more what I say. ‘The thickness of the 
wall is about 0°3 w, and in the net projections 1:2 wu, we thus 
obtain an image of simple inner cell-envelope thickenings in a 
manner leaving nothing to be desired, and which has not the 
slightest similarity to Tvriceratium. The cell-wall of the middle 
girdle differs inasmuch as the thickening lines producing the 
markings are undoubtedly on the outer side. The wall-thickness 
is so extraordinarily small that with a magnification of 1000 it 
appears only as a mere line. The net-lines are also very flat, 
about 0°7 w in height. With reference to the girdle-band 
one can speak with full conviction of a surface-sculpture, whilst 
with the valves one must say inner surface-sculpture. Here 
may be added that Isthmia has a large cell-nucleus lying in the 
inner granular protoplasm, and which was touched by me several 
times in my sections. It is a spherical transparent vesicle of 16 
diameter, having a spherical nucleolus of 4:5 w in diameter. The 
result obtained from surface views of dry imbedded Isthmiz does 
not at all agree with that obtained with the transverse section 
images; the thickening lines appear like strong refracting masses, 
and were looked upon as such by the earliest investigators 
(Ehrenberg, Kiitzing, and others). It was not at all to be expected 
from an @ priori examination that the sculpture of this species 
would appear so totally different from Triceratiwm. I shall not be 
expected to enter further into the researches of Slack (25), according 
to whom the membrane consists of small spheres. 


8. Achnanthes. 


If an obstinate defender of the opinion that diatom sculpture 
consists of inner cell-wall thickenings, wishes to secure an object 
substantiating his view, I can very strongly recommend to him the 
large forms of Achnanthes. After having occupied myself inland 
for years with fresh-water diatoms, on meeting with the marine 
Achnanthes I believed I had found the long-searched-for proof. 
Each surface view under a good Microscope shows clearly the 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 673 


projection of lines on the inner side of the membrane, whilst the 
outer side is perfectly smooth. It can be seen more distinctly in 
sections, but in proceeding we shall soon have to admit that a part 
of what we stated has to be reconsidered. The following relates 
only to Achnanthes brevipes Ag.* 

§ 1. We have to distinguish three sorts of markings in 
Achnanthes. This diatom has an unsymmetrical shape at the 
division-plane, so that only the two middle sections vertical to this 
plane give symmetrical halves. Therefore we get:—(1) A dorsal 
valve characterized by greater convexity; it has a mid-rib without 
nodule running evenly from one end to the other; close to it 
run the smooth transverse lines, the interspaces of which are wider 
than those of the ventral valve; between every pair of transverse 
lines are seen in most instances three rows of dots, sometimes only 
two. (2) A ventral valve, characterized by a thick depression in 
the middle; it has a mid-rib with even striz on both sides, in the 
centre a large nodule which at right angles to the mid-rib extends to 
the edge, thereby producing, the same as with Stawroneis, the 
image of a cross. ‘The transverse lines are finer than in the dorsal 
valve; between each pair, as a rule, one row of dots, sometimes 
two. (3) The girdle-band, always with delicate striz vertical to 
the division-plane, which however is subject to variations as we 
shall presently see. The figs. 33, 37, 38, and 39, plate X., of 
A. brevipes sufficiently illustrate this description. 

Two good serial sections are obtained, running vertical to the 
division-plane and to the two mid-ribs (in fig. 33 this is delineated 
by lines 1-3); the third series I made approximately parallel to 
the division-plane. My attempts in the third direction of space 
(the horizontal) failed. From one of the two former series, 
numbering twenty-three sections, I have delineated three, viz. 1, 5, 
and 15, figs. 40-2, plate XI. No.1 is a marginal cut; 23 has 
nearly the same appearance. No. 15 cannot be far from the middle, 
because among the succeeding numbers are a few of too great 
thickness. 

Examining first the general form, we see from the sections 
in which all three conform, that the ventral valve is depressed, 
trough-like, along the mid-rib, whilst the dorsal valve appears half- 
cylindrical, that is to say, rounded off convexly. By this feature 

* The difference between A. brevipes and longipes Ag. is often very great. 
A. longipes commences with a short pedicle ; the pointing or rounding of the valves 
is somewhat variable, and the distance between the striw is not always definite. 
From the stria distances and the length of the pedicle, I believe I have deter- 
mined the specimens investigated to be A. brevipes, but they might belong to 
A. longipes. The specimen figured by Pfitzer as A. brevipes (19, pl. vi. fig. 15 s) 
I should rather suppose to be A. ventricosa Ktz.; anyhow, this variety is not 
the one investigated by me under the name of A, brevipes, I have found 


A. ventricosa on the sea-shore near Sylt, but could not make use of it in the 
present investigation (vide 5, p. 737). 


674 Transactions of the Society. 


we are able to distinguish either valve even with imperfect sections. 
The convexity of the dorsal valve fits nearly into the trough of the 
ventral valve, so that they touch each other when of large size. 
The section-bundle consisted of three frustules, of which the lowest 
was probably near the period of its second division, whilst the other 
two had only recently emerged, therefore the lowest, compared with 
the others, is probably backward in development. The girdle-band 
comprises only the limit-line between the lowest and middle frustule. 
With reference to the fine sculpture, mention must be made of a 
portion of membrane hitherto unobserved, and which could not 
have been well detected without transverse sections. This is the 
projection on the edge of each valve, that is to say, at the limit 
between valve and girdle-band, a spine turning far inwards as 
shown in the figs. (r /), and is found fourfold in each frustule. All 
sections of the two series prove clearly these four projections; they 
can only be the expression of a projecting line running along the 
edge towards the inner space of the cell, I will call it edge-line, 
which with the usual division of the frustule plays a prominent 
part as we shall see. With low powers one sees only the four 
small spines; applying the highest power one observes that the 
larger spines, at any rate, are hook-shaped towards the valve-cavity, 
fig. 43; it may actually become a hook, fig.46. ‘The end-valves, 
being the oldest in the row, have the largest hooks and the strongest 
edge-line. In the youngest valves one sees the partially developed — 
hooks, sometimes hardly nodule-shaped, fig. 44. 

The largest hooks penetrate 2 m into the cavity of the cell. 
After having discovered the marginal lines in the sections it became 
easy to trace them again in the surface view; they are particularly 
well seen in balsam preparations (in consequence of the weaker 
refraction of the walls). The older investigators, for instance, 
Kiitzing (plate 20, [X., 1) and Ehrenberg, figure distinct dark 
marginal lines ending with a nodule. The transversely cut marginal 
line is in section far more conspicuous than the mid-ribs; in most 
instances one sees the mid-ribs as round nodules standing off the 
membrane ; occasionally they may be seen somewhat more distinctly. 
Altogether the dimensions are very small, and only in the most 
favourable instances can one determine that they project inwards 
and not outwards. The valve surfaces are always seen in good 
sections as distinct rows of dots, pearl-like, and this is the expression 
of the fine dots of which I spoke above. These pearls I declare 
to be, according to the best and most reliable sections, chambers 
closed on all sides situated within the membrane. ‘The direction of 
the cuts in the series in question being parallel with the actual 
transverse striz, one can hardly expect to discover anything about 
the condition of the latter. But if the section is very thin, one 
sees on the inner side of the pearl row a fine straight line depressed 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 675 


at the mid-rib, fig. 45, so that at the side of it are two thin 
membrane-strie free from dots, such as we demonstrated in the 
surface-image. ‘This fine line I consider to be the limit of the 
inward projecting transverse striz, and also of the one touched 
by the section ; for if it is thicker and comprises two transverse 
strie, it will be looked for in vain in this image, because the 
interference at the margin then becomes so strong that we can give to 
the line any interpretation we please. The central nodules and their 
expansion are not met with with certainty in either series ; unfor- 
tunately they seem to have broken off at the touch of the knife. 

The girdle-band in old valves has always a distinct row of coarse 
strie ; in the surface-section, fig. 40, this is magnificently brought 
out. These strize are about half as fine as the transverse stric of 
the ventral valve. In the younger part of an old valve, or in a 
young valve, the striz on the girdle-band are very indistinct. In 
the transverse sections, inasmuch as the sections are in the direction 
of these striz, nothing can be seen ; one observes no differentiation 
whatever in this membrane except that sometimes irregularly a dot 
appears on the inner side, which may indicate the delicate lines 
running parallel to the marginal lines. The whole matter is to me 
doubtful. I cannot explain the extremely fine structureless section 
occurring at the margin of the surface section 1. Since the girdle- 
band has no such non-striated portions in the surface view, it may 
possibly be an outer substance hardened by the alcohol. 

The serial sections which were made in a direction 90° from 
the preceding (22 in number) cut through the surface from first 
to last; but shortly after the first and shortly before the last, as a 
glance at fig. 33 discloses, the transverse lines of the strongly 
porous valves must, at the point where the two sides run parallel, 
haye been struck exactly vertical to their direction. This, as a 
matter of course, occurs likewise with several valves situated between 
the two ends. Further, the girdle-band is seen in several sections, 
and is cut vertically to its strie. The most suitable sections 
through the part of the dorsal valve under examination, as repre- 
sented in fig. 48, show that the transverse lines, as we learnt from 
the surface view owe their origin to the delicate but distinctly 
raised thickening lines on the inner side of the membrane. These 
fine lines are about 0°9 w high, the membrane itself is 0°5 wu thick. 
In examining the sections near to the last one, one detects the 
fact not quite so distinctly in those which are unquestionably 
taken through the ventral valve, but I have obtained with a well- 
regulated position of one section an unequivocal image, fig. 47. 
Between the transverse striz lies the chamber, seen only with very 
fine sections, fig. 50. As a matter of course, the valve-section is 
in places entirely surrounded by the adjoining girdle-band section. 
The girdle-band can always be easily distinguished in these sections 


676 Transactions of the Society. 


by its peculiar regular fine pearl-like sculpture, figs. 45 and 52. 
Now, what are these pearl rows? I believe they must be inter- 
preted similarly to the sections of the Flensburg Plewrosigma 
described by me (6, pp. 475-8), hence, in this case, probably a long, 
extended, cylindrical chamber within the membrane. The apparent 
projection on both sides of the surface must be an optical effect. 
Clearness in these details with the extreme delicacy of the object 
is hardly to be expected. The central nodule of the ventral valve 
is a strong inward-projecting thickening, without any other dis- 
tinction except that from every side it sends off a thinner line in 
the transverse direction to the edge of the valve. 

§ 2. With this we conclude our examination of sections in 
general. I believe I have thrown some new light on the com- 
plicated structural details of the species Achnanthes, although I 
admit that much remains to be done. With the ample material at 
hand it became interesting, apart from the above results, to make 
the attempt to discover the development-processes which take place 
in the gradual formation of these sculptures during ordinary 
fission. Now that we know more exactly the connection of the 
girdle-band with the valves, the former, not being structureless like 
most of the fresh-water diatoms, will probably furnish data for 
further elucidation of these hitherto obscure problems. In aid of 
further research we should algo avail ourselves of simple surface- 
views as well ag the examination of numerous freshly imbedded 
and well-preserved specimens in balsam, because with the help of 
transverse images the appearances can be correctly explained. I 
do not hesitate to add here the observations which I have made 
with a larger number of balsam specimens of Achnanthes. brevipes 
even at the risk of engaging in controversy. 

Taking a recently divided specimen, such as is shown in 
fig. 83, and examining it with reference to the formation of the 
girdle-band, one finds that between the two valves, viz. between 
the one older and the one younger, there is no space. We observe 
the marginal line, and close to this extends the young valve. If we 
keep well in mind the image of the marginal line of another fuller 
grown specimen, we shall be easily convinced that the younger 
specimen has only one single line. Fig. 33 shows the frustule at 
the edge where the young valves have only recently obtained the 
necessary solidity to enable them to withstand the influence of 
contracting fluids (I might have started from earlier stages, but my 
objects not hardened with osmium show all sorts of bendings of the 
young valves which I attribute to the modus operandi). Adjust- 
ing the left cell as the optical middle section one sees the edge-line 
. of the old dorsal valve like projecting nodules: close adjacent 1s a 
smaller nodule which can be nothing else than the commencement 
of formation of the marginal line of the younger ventral valve. On 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 77 


the surface of the frustule such a second line cannot yet be traced 
at all; on the contrary the transverse striz of both valves run to 
the apparently common marginal line. This companion cell on 
the right is in this respect slightly more developed, especially at 
the one end (the lower in the figure). Not only is the small 
nodule more distinct in the middle section, but it is also more 
distant from the larger, and on the surface one can clearly see two 
marginal lines not quite parallel. Fig. 34 gives the line of the 
optical middle section again, but more highly magnified. Turning 
now to another still younger specimen, fig. 35, we observe the two 
marginal lines slightly further apart. The divergence of the lines 
continues until the cell obtains the requisite breadth to divide anew, 
fig. 37. The question arises with this divergence, what becomes of 
the girdle-band and how is a new one formed? With regard to the 
old, one sees clearly the edges are extending over the other, of course 
mostly only with an immersion objective, and it would easily be 
overlooked if we did not know where to search for it from Pfitzer’s 
pioneer work. With regard to the processes accompanying the 
formation and development of a new girdle-band we find but little 
information in Pfitzer (19, p. 56). He states that the girdle-band 
in Pinnularia is formed unusually late, only after the new valves 
are complete, and then where it adheres to the valve; that it ig 
seen almost at first in its definite thickness reaching slowly to its 
normal breadth. According to Pfitzer (19, p. 9) the girdle-band 
has an outer edge in organic connection with the valve, and an 
inner free edge touching the other ring but not grown together. 
With Achnanthes—and here the non-existing marginal line 
of Pinnularia renders capital service—we can establish with all 
desirable certainty that the girdle originates in these lines. One 
has only to go backwards in the various stages of development in 
order to establish the fact. At the point where the distance 
between the old and the young line can be well observed, one sees 
distinctly with an oblique position, fig. 36, that the cell-wall 
between the two lines is of double thickness, hence at that point 
there must be already a younger girdle-band. Of course, with the 
extreme thinness of the two bands the duplicature cannot be 
observed directly ; the line expressing one cleft extends, as far as I 
see, up to the young marginal line, fig. 36,77. But since this 
was attached originally to the older line, the girdle-band without 
doubt is so far a double membrane, as it has already been rendered 
probable by its thickness. Following up backwards this very thin 
narrow girdle-band, fig. 33, on the left, we find here its origin 
in the depression of the marginal line. We further deduce 
from these Achnanthes images that, according to my exami- 
nation, it is clearly evident the girdle-band from its commencement 
is attached to the cell, since it fills up entirely the inner space 


678 Transactions of the Society. 


between the two marginal lines. From this I deduce further: 
there is no free edge of the girdle-band, such as Pfitzer has 
described with Pinnularia, anyhow not so long as the cell is only 
of moderate breadth ; both edges are grown to it.* 

When this connection ceases must be discovered by future 
researches. But there can be no doubt that at some time or other 
a process of forcible separation must take place. This separation 
always occurs in a segment of the old marginal line. We are 
therefore justified in stating that at that spot the new formation of 
cellulose takes place, whilst further on towards the new line, the 
membrane is already solidified and capable of resistance. Some 
proof of the correctness of this view is found in the development 
of a strong margin near this spot; the lines become weaker the 
further one goes from this margin. In the cell, shortly before divi- 
sion, fig. 37, the tearing-off of the young girdle-band has taken 
place. This looks like the signal for a new division; at the 
moment of tearing off, the compressed contents in the rigid cell- 
envelope become suddenly free, at least in one direction, and can 
hence extend, inasmuch as the girdle-bands are drawn out like 
telescope-tubes. If these views are correct they lead us to the 
conviction that the older outer girdle-band is a safety-sheath for the 
inner younger girdle-band ; it prevents injuries to the latter whilst 
partially in a non-silicified condition; it protects with its older 
strong portion the younger recently formed annular portion of the 
inner band. From this may be deduced that Achnanthes is in 
many respects similar to the growth of the cell-envelope of 
Cidogonium (may we say to the large marine Conferve ?).t 

We must now cast a glance again at the sections. None of 
the uninjured (fig. 43) confirm these assertions; one observes from 
marginal line to marginal linea fine simple membrane, consequently 
without doubt twofold. But only when a section is injured and 
its substance has been slightly removed by the knife during the 
operation of cutting is the real state of affairs brought to view. In 
fig. 44, otherwise very similar to fig. 43, we see a portion of such 
a section in which the young girdle-band can be traced; a de- 
pression being nowhere observable in the space up to the old 
marginal line, the girdle-band must have grown there. We also 
find in such slightly injured sections clear proof that it easily tears 
off at the old marginal line. If I wanted to convince the reader of 


* I might mention en passant the physiological objection against the non-con- 
nection of the two valves, that the water must find access to the inner space, 
however narrow, and would thus come into direct contact with the protoplasm, 
through which the latter, according to all established experience, would swell 
and possibly effect a separation of the halves. 

_t Whether the enlargement of the cell-envelope of Rhabdonema adriaticum 
(wide Nageli and Schwendener, 17, p. 544) hasits cause in a similar law seems to 
me to require fresh investigation. 


The Structure of Diatoms. By Dr. J. H. L. Fligel. 679 


the accuracy of these views which I acquired in the examination of 
the sections, I should have been obliged to photograph an entire 
series. 

The question whether the diatoms become smaller through 
repeated division can be well elucidated with Achnanthes, espe- 
cially if one is possessed of richer material than I have, and by 
examining and comparing the measurements. In doing this we 
should start with the marginal lines of very young specimens. 
What I have seen in my examination of Achnanthes preparations 
confirms the results obtained by Braun and others, especially 
Pfitzer (19, pp. 20-8, 100-102) with Himantidium. I confess I 
see several specimens in which the younger valve is shorter than 
the older; but I have also found some where the length is greater 
than in the older, which may possibly be caused by the girdle-band 
having enlarged itself at the edge. The normal condition appears 
to me to be an exact equality of both valve-lencths. On the one 
hand this follows from the manner above described in which the 
first traces of the young marginal line are developed, fig. 34, and 
where with the best methods of measurement no difference will be 
found. On the other hand one sees, by careful examination of such 
young cells, that the older girdle-band is always slightly raised, 
that is to say, about as much as its thickness 0°4-0°5 w; to this 
extent it grows over the old valve. Next, one can often see with 
Achnanthes longer cell-rows in connection, all of equal size. This 
has been minutely discussed by Pfitzer. We have lastly in 
Achnanthes in so far a very favourable object, that the valves are 
not similar as with Pinnularia and Himantidium, but on the 
contrary are very different, and no definite judgment can be arrived 
at with regard to age and number of generation. Now, if I 
examine a few good rows composed of eight frustules, where for 
example the lowest and oldest ventral valve is together with the 
youngest dorsal valve coming out of the third division, then I find 
no difference in size between the grandfather and the great-grand- 
daughter, although the threefold thickness of the girdle-band, 
always a good measurable size, would have to be deducted with 
the latter if Pfitzer’s theory were in this instance correct. How- 
ever, who will guarantee that we have here to do with the grandfather 
and the great-granddaughter? ‘The hundredth division may already 
have taken place, since it is known that in time only individuals 
connected by mucus are thrown off. All considered, I am of opinion 
that Achnanthes contradicts rather than confirms Pfitzer’s theory, 
and that the supposed corrective of the cell diminution, namely, 
the formation of auxospores, may have other purposes. The decision 
of this question must be left to future investigators. Whether the 
corner of the ventral valve developing the longer or shorter spine 
by which this diatom is fastened on other alge, is of different 


680 ~ Transactions of the Society. 


structure from the one at the other corner seems probable at the 
first glance, but nothing definite on that point could be made out. 
It seems to me that the spine is the outdrawn end of a general 
gelatinous cover secreted by the entire valve-surface. The cell- 
nucleus of Achnanthes, fig. 46, is a small spherical vesicle of 4 u 
in diameter with nucleolus of 1 p. 


9. Synedra. 


With Achnanthes I have given numerous transverse sections of 
Synedra Gallionit Khrenb., often and everywhere found in Kiel 
harbour, fig. 53. Beyond its general form very little can be 
deduced, especially as we are left m the dark as to how the in- 
significant transverse strize are caused on the edges of the square. 


Ill. Resuuts anp GENERAL REMARKS. © 


The detailed researches given in the preceding chapters shall 
only be mentioned here in so far as they relate to the sculpture of 
the cell-envelope, whilst I must refer to the above for the facts in 
connection with the girdle-bands, fission, &c. These researches 
comprise in all, seventeen varieties of diatoms (Pinnularia major, 
viridis, and Crabro; Navicula Lyra; Plewrosigma balticum, 
angulatum, Scalprum ; Surirella biseriata; Triceratium Favus ; 
Coscinodiscus radiatus, oculus iridis, centralis, and concinnus ; 
Isthmia enervis; Hupodiscus Argus; Achnanthes brevipes, and 
Synedra Gallioni), which have all been examined by the section- 
method, also to some extent by other methods. The result is that 
the marking of the diatom coatings has its origin in various forms 
of the wall-thickness and in the cavity formation within the 
membrane. The results can be grouped as follows :— 

The marking is caused :— 

(1) by the sharply projecting wall-thicknesses. 

a, on the inner surface of the membrane: 

Achnanthes = transverse strize, Isthmia = valves, 
probably also Grammatophora, Epithemia, and 
others. 

b, on the outer surface of the membrane: 

Isthmia = girdle-band. 

(2) by developed chambers within the membrane, and 

a, with distinctly observable openings. 

* Which are on the outer surface of the cell, whilst they 
are closed inwards (in a certain degree transition from 
type 1 b): 

Triceratium, Coscinodiscus radiatus, and possibly a 

few other varieties. 


+ Weiss, 28, p.9; Miiller, 16. 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 681 


** Which are situated on the inner surface of the membrane 
where the chambers at the same time have the 
enormous extent of almost half the breadth of a valve, 

Pinnularia, and probably all single striated forms. 
b, without distinct openings, but of considerable size. 
* With quite smooth chamber-walls: 
Coscinodiscus centralis, and others. 
** With nodular thickened chamber-walls : 
Eupodiseus. 
c, closed on all sides, and extremely small, approaching the 
limit of discrimination : 
Plewrosiqgma, Navicula Lyra, Surirella, Achnanthes 
(the finer marked variety), and probably most of 
the finely dotted striated forms, 


Having thus given proof of the existence of various types as 
the cause of the surface-image, the necessity arises of refuting those 
investigators who constantly talk of a diatom sculpture in general, 
of surface-sculptures, of furrows, cup-like depressions, hemispherical- 
shaped prominences, &c. In so far as this has not already been 
done in my paper I now undertake the task. 

Prof. Weiss propounded in 1871 (28) an entirely new view 
of the sculpture of diatoms, which is formulated by him (pp. 15-6) 
as follows: “ The markings of the various diatom species, however 
different they may appear under low magnification, differ only 
apparently ; under high magnification, and with a correct inter- 
pretation of the sculpture, all diatoms are constructed on the 
same principle, namely, they consist of more or less polygonal 
cellules, the walls of which, with low magnification, produce and 
condition the configuration of the so-called markings.” The inner 
cavity he compares (p. 9, footnote) with the embryo-sac of the 
higher plants. ‘The notion that the envelope consists of numerous 
minute cells is so thoroughly erroneous that we need not quarrel 
about it. ‘The attributes of a cell do not consist, aczording to our 
present knowledge, in the wall alone which surrounds a cavity, 
and it is impossible to look upon each cavity as a cell-lumen even 
if it should have regular form. ‘he discovery of nuclei within 
the so-called cells (p. 30) must be traced back to an error in the 
examination ; they would never have escaped me in my manifold 
staining processes. Nuclei which take up no colour I may say 
do not exist. ‘The idea that all diatoms have a common sculpture, 
I contradict most emphatically. I cannot at all comprehend how 
Prof. Weiss, with his great knowledge of details, and with the 
enormous quantity of material at his disposal, can have arrived at 
such an opinion. We must, however, give Weiss the credit that 
he was the first to demonstrate that the presence of cavities closed 

Ser. 2.—Vou. IV. 22 


“682 Transactions of the Society. 


on all sides was the cause of the marking during the development of 
the valve. Considering the criticisms Weiss’s work has experienced 
through the erroneous theory of furrows, sculptures, &e., the credit 
due to him must be kept prominently in view. 

Of similar tendency are the works of Count Castracane, for 
which I refer to Just’s Botan. Jahresb., 1873. It will be equally 
unnecessary to enter upon their contents. 

I have at various times in the course of this paper referred to 
Prof. Pfitzer’s epoch-making work (19). I am obliged to speak 
of it once more, because at the conclusion, speaking generally of 
the cell-envelope of diatoms (p. 174), he reproaches me with having 
in my Pleurosigma researches insufficiently estimated the possibility 
that the connections between the two surfaces of the cell-wall are 
distinguished from the interspaces by the stronger refractive power 
due to the molecular constitution. Then he refers to the bast-cells 
which have similar sculpture, and as worthy of notice he mentions 
that with diatoms differences could not usually be due to water, 
but to silica-contents. I do not know Pfitzer’s reason for this 
statement ; I have fully explained (6, p. 474) that I have examined - 
fresh specimens which had been boiled in nitric acid and in chlorate 
of potash, and further (p. 485) that through continued boiling the 
sculpture does not alter. In the latter case, surely nothing else 
but silicic acid remains; then what does he mean by making a 
difference by saying silica-contents? The transverse section of a 
boiled valve shows exactly the same walls as previously. It 
appears to me that my demonstration of closed cavities came to 
Pfitzer’s notice at an inopportune moment, because in the same 
journal he brought forward his furrow theory which, as we have 
seen above, is wrong in every respect. Since Pinnularia seems to 
be the only diatom examined by Pfitzer by the section method, in 
order to discover its sculpture, he adopted it as the type of diatom 
sculpture, and when, soon afterwards, Miller proved real outer 
openings in Triceratium and tried to make useless corrections of 
my work, Pfitzer evidently believed that I had fallen into error, 
and that his so-called surface-sculpture was a property common to 
all diatom frustules, Pleurostgma included. In proof of this, one 
need only glance at Pfitzer’s subsequent writings. Let me only 
draw attention to his latest (20), from which we might infer that 
it expounded to some extent the latest views on the subject. But 
about the structure of the cell-wall it contains nothing other 
than Pfitzer’s furrow theory, and O. Miller's sculpture of 
Triceratium. 

Another paper which we have to discuss is by Prof. Abbe: 
‘ Beitrage zur Theorie des Mikroskops.’ In this work (1, p. 450) it 
is demonstrated “that all the finer sculpture of an object, of which 
the elements are small and close enough to produce by their 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 683 


proximity an observable diffraction phenomenon, are not imaged 
geometrically in the Microscope, that is to say, not as if the homo- 
focal emergent pencils of rays from the object represented it point 
for point on one image-surface.” From this he draws the con- 
clusion (p. 453)—“‘all attempts to determine the sculpture of the 
finer diatom-valves by morphological interpretation of their micro- 
scopical images seem founded on inadmissible premises. Whether 
Pleurosigma angulatum has two or three systems of striz or 
whether real striz are there at all, or whether the observed mark- 
ings are caused by isolated elevations or isolated depressions no 
Microscope can determine however perfect it may be or however 
strong its magnifying power.” Further (p. 454)—“ that the same 
condition of things exists very nearly for a great number of purely 
organic images in histological work, can be learnt by the example 
of striped muscular fibre. In good preparations the diffraction 
phenomena can be easily observed, and their effects in the micro- 
scopical image can be studied experimentally in the former-described 
manner. The manifold differences in the character of the image 
explain to some extent the disputes which have arisen between 
different investigators on this point; but at the same time they 
also establish the impossibility of stating anything definite about 
their real organic composition in the sense of the attempts made 
hitherto.” 

I am not aware whether Professor Abbe still clings to these 
views expressed in 1873, or whether he has since convinced himself 
of their error. From his publications which I have since occa- 
sionally seen, I believe he still holds to the former opinion. These 
theses figure as principal results in a journal of eminence, which 
must be read by everybody who wishes to keep an account of what 
he sees in his Microscope. Therefore I consider a refutation of 
these theses in this place a necessity. 

Since the structure of muscular fibre and the differences 
amongst histologists of that date are put forward as examples of 
the correctness of the assertions, it may be well to bear in mind 
that the greater number of histologists have not adopted in their 
researches Prof. Abbe’s views; and that now-a-days the com- 
plicated structure of the transversely striated muscle-fibre is nearly 
established. ‘This is not only valid as regards the single layers 
composing the fibre, but also for the double-refraction of certain 
parts, of which Abbe also states (p. 453), it was futile to entertain 
the idea. I will not here enter into the full details how, at the 
commencement of the last decade, the confusion chiefly brought 
about by Heppner’s wrong views about the muscle structure was 
dispelled by my work ®) based on the examination of an unusually 
favourable object, and I likewise demonstrated at the same time 
that with the application of good hardening methods one can 

222 


684 Transactions of the Society. 


obtain similar results on other objects, but less distinctly. Shortly 
afterwards, the classical works of Engelmann, and more recently 
of Merkel, whilst confirming the complicated muscle structure and 
further by investigating the relations of the elementary particles 
before and after the contraction, have closed the question for some 
time to come. 

If after this Prof. Abbe’s objection against muscle sculpture in 
general is tacitly accepted as set aside, then, in view of the fact 
that among the numerous diatom investigators hardly one has 
seriously occupied himself with the structure of diatoms, it becomes 
all the more difficult to controvert Abbe’s views since I am the 
only one to whom falls the task of domg so. I must not forget, 
however, that Dr. Altmann has every now and then vindicated my 
views against Abbe.* 

It would lead too far away from our subject if I were here to 
enter on the merits of their differences; he who takes an interest: 
therein should read Archiv fiir Anat., 1880, pp. 111 e¢ seg. In 
our present discussion it is enough that all my results obtained 
hitherto are in direct contradiction to Abbe. Any one desirous of 
arriving at a definite opinion can inform himself by my diagrams 
and photographs, or by repeating my experiments. Suppose the 
student in microscopy investigates the sculpture of an object which 
is unknown to him, limiting himself to the surface-view only, say, 
for instance, the Plewrostgma valve, it is certain that he will be 
unable to solve various doubts, and in this I quite agree with 
Prof. Abbe; he will not be able to decide whether certain lines 
are raised or depressed, whether they are situated inside or outside ; 
on this subject microscopical literature records the most unfruitful 
squabbles. But if the investigator examines the object by sections 
and makes casts of the surface, and makes use of the staining 
processes, &ec., and finds, for example, exactly at the place of a 
previously doubtful line a projection, then it becomes immaterial to 
him whether the Microscope deceives us in the surface-view and 
gives images which do not correspond to reality. If the Micro- 
scope deceives us in one case, then it also does so in others. The 
change in the methods of investigation puts us in the position to 
find out the truth. As soon as the investigator takes the result 
obtained by all his methods and compares it with the surface- 
image, he will in most cases have answers to all his questions 
without being obliged to enter into the depths of the diffraction 
theory. I observed these maxims in my work on Pleurosigma 
sculpture, and I hold to them at the present day. 

‘'o this cannot be opposed the fact that one can obtain by 
artificial means images like diatom markings, and such diffraction- 


* Personally I do not know Dr. Altmann, therefore I take this opportunity 
to tender him my best thanks. 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 685 


spectra as diatoms produce, and that therefore the microscopical 
image is unreliable, and that for this reason no Microscope could 
clear up the true facts. The first portion of the sentence I admit, 
but the second I deny. That the half wave-length of light a 
praxis indicates the limit beyond which in 1869 no Microscope 
showed details, I had clearly demonstrated in my paper on the 
optical appearances in diatoms (5); the great honour of having 
proved theoretically the existence of this limit is due to Prof. 
Abbe. I had surmised conclusions on the results of my diffraction 
studies on the finer sculpture details, which | considered unreliable 
after having successfully used the section method. Several other 
objects furnish diffraction-spectra, although they are of totally 
different sculpture which we cannot bring into parallel with the 
diatoms: for instance, butterfly-scales,* and the skin of the 
Ascarides whose diffraction phenomena have been studied by 
Leuckart (12, vol. ii. p. 164). From the latter nobody can arrive at 
definite conclusions on the sculpture; but it would be wrong to 
assert that no Microscope in the world could elucidate it. Summing 
up we may say: the diffraction phenomena suggest only the 
existence of small particles of approximately equal size in layers, 
but they convey nothing as to their form or arrangement. The 
diffraction theory does not put a stop to the closer investigation of 
the sculpture of muscles, diatoms, &c., and Abbe’s assertion that 
we could never arrive at anything reliable about this sculpture is 
unfounded and was practically refuted at the time he published it. 
With this I believe to have given sufficient courage to all timid 
students to continue their researches which otherwise would be 
without prospect as long as Abbe’s opinion predominated. 

The latest work by Prof. Strasburger (27, p. 143) treating of 
the sculpture of the cell-wall of diatoms, mentions me with the very 
unflattering sentence—“ F'légel believed he had found out that the 
cell-wall contained chambers opening above as well as below.” 
Then comes O. Miller who proves the opening with Triceratiwm. 
I may expect that Prof. Strasburger after reading my present 
work will alter his views considerably. Should I be disappointed 
therein the way would be open to him to investigate the matter 
himself personally, and I own that among all living botanists, I 
consider him to be the most able to assist in solving the question. 
Should he in such case also “believe” he has arrived at results 
slightly different from mine, I would request him before presenting 
the world with his results to try again a second and a third time 
with different weather, with other sections, and with other physical 
disposition personally, and then he will soon convince himself that 
his former “ belief” was unbelief. 


* About their finer sculpture I shall publish my investigations shortly in a 
zoological journal. 


686 Transactions of the Society. 


If in the preceding pages one or other essay on this subject, 
which has appeared during the last decade, has not been mentioned, 
I would ask indulgence on account of the seclusion of my place of 
residence; but I believe that no essential questions regarding the 
subject have been overlooked. 

With this I conclude my work, and for the present, on account 
of otker studies, I take leave of a subject to which I owe many 
pleasant hours of my lifetime. Whether the text-books of botany 
will take notice of the fruits of my investigation, or whether they 
will adhere to the old mistakes, may be left to the future. Up to 
the present I have only seen one work, the excellent synopsis of 
botany by Leunis, newly edited by Professor Frank, which gives a 
true account of the newest standpoint in these questions. 

Only by constant and persevering work can we expect further 
progress; it cannot be done by the mere purchase of expensive 
immersion objectives. He who will only judge from a usurped 
high position; he who believes he can do something by setting up 
diffraction theories; he who looks upon diatoms as aggregations of 
erystals; he who believes he can decide upon all sculpture questions 
by observation of the surface; he may keep to his own errors, but 
he must not expect that I should answer his attacks which he has 
based upon such means in order to find fault with my work, how- 
ever learned may be his phraseology. Considering my positive 
results, I must be excused in saying that I will not enter into dis- 
cussion with such opponents. The literature of the last decade 
furnishes so many cases where persons who, after their own more 
or less special occupation with diatoms, look upon themselves as 
important microscopists, bring to light the greatest imaginable 
nonsense relating to sculpture questions. If I cannot indulge in 
the hope of putting a stop to this by my present work, it will 
no doubt contribute much for the intimate knowledge of these 
interesting organisms, and when in future the structure of these 
cell-walls is in question, the works of Pfitzer and Miller will 
not be exclusively referred to, but precedence will be given to 
an investigator who ten years ago put the leading facts into 
clear light. 

Lastly, I have to thank those scientists who sent me their 
papers, also Herr Moller, of Wedel, for sending various material for 
investigation. 


EXPLANATION OF PLATES. 


All the figures have been drawn by the excellent 1/18-in. objective of Dr. Hugo 
Schroder. All are magnified 1550, unless otherwise stated. The variety in the 
amplification is due to the change of the eye-pieces and the alteration of the 
correction-adjustment. They are, with the exception of fig. 7, no flighty 
sketches, drawn after mere eye measurements, but all dimensions are based 
on micrometrical measurements. 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 687 


Puate VIII. 

Figs. 1-7.—Pinnularia major. 
ha, showlet 
me, median 
1 e, lateral \ ends of the same. 
k 6, entrance to the chamber. 
mn aes } edge of the opening. 
m i, mid-rib. 

Fig. 1—Transyerse section through a valve touching the chamber-openings 
somewhere in the line at 4 in photograph 1 (or perhaps nearer the central 
nodule). 

Fig. 2.—Transyverse section about the same place, line 5, in which is contained 
the vertical. partition-wall between two chambers, the openings indistinct. 

Fig. 3.—Middle portion of a sim'lar transverse section to illustrate a very 
common appearance of the sloping away of the middle furrow. s, the closing 
envelope which in many cases is torn during cutting, whereby balsam enters 
into the cleft and produces the appearance of a continuous cleft through the 
entire membrane. 

Fig. 4—Transverse section touching the centre of the central nodule (line 3 
in photograph 1). 

Fig. 5.—Part of a longitudinal section touching the chamber openings, i. e. 
in the direction of the dotted line 1 in figs. 1 and 2, or photograph 1. af 
outer surface, and if inner surface of the cell-wall; % wv, a vertical partition- 
wall between two chambers. . 

Fig. 6.—Portion of a longitudinal section along the side of the cliamber 
openings, i.e. in the direction of the dotted line 2 in figs. 1 and 2, or photo- 
graph 1. ‘he membrane on the inner surface is much stronger than that on the 
outer surface. 

Fig. 7—Diagrammatical figure of a collodion cast. a, a single T-shaped 
continuation in side view (as it becomes elucidated by the different focal 
positions). }, a group of the same, in perspective as seen from above. 2, the 
smooth collodion surface. c, a piece of the serrated stripe which is formed 
along the chamber openings, and on which the 'T continuations stand like a row 
of trees. x, the collodion thread which was in the chamber. y, the spine of the 
same, which in consequence of the collodion contained in the opening contracts. 


Fig. 8.—Pinnularia (Naviculi) Crabro. 


Transverse section from the middle of the valve. % a, chamber; & 6, opening 
of the same. yg}, girdle-bunds; the outer has in all sections the pusition 
figured; the second valve is wanting. 


Figs. 9-12.—Navicula Lyra. 

Three sections out of a series of 27 transverse sections through one valve. 

Fig. 9—Middle section (No. 13) touching the central nodule mk, which 
forms at that point a very flat thickening. 4a, chambers. 

Fig. 10.—Four sections further on (No, 17). mr, mid-rib. / p, lyra plates. 
k a, chambers. 

Fig. 11—Section near the end of a valve (No. 1). 

Fig. 12.—Small portion of the surface-view of a valve of somewhat consiler- 
able size, corresponding to fig. 10. 


Puate IX. 
Figs. 13-20.—Surirella biseriata. 


q |, transverse ribs. 

m 7, mid-rib. 

fl, wing. 

rr, marginal tube in the wing. 


688 Transactions of the Society. 


Figs. 138-19 x 830. 
Fig. 13.—Transverse section No. 2 


” 4. ” ” » 9 

Pela: re 9 », 39 ) through one and the same valve. 

” 16. ” ” ” 40 

9 17. eae ”? 9 66 

» 18.—Portion of the longitudinal section No. ) through one and the same 
», 19.—Longitudinal section » 8) valve. 


20.—Portion of the section No. 8. 


The longitudinal section, fig. 19, corresponds to the dotted line in the 
transverse sections figs. 15 and 16. In figs. 13, 15, and 16 the more faint contours 
indicate the outlines of the membrane with slight change of focus, corresponding 
to the undulations in fig. 19. The small continuation f at the edge of several 
transverse sections is probably due to the adhesion of the girdle-band. 

The thick longitudinal section fig. 18 comprises nearly the entire wing; the 
fig. in consequence shows a portion of the wing in surface view. a, the places 
where both membranes of the fold cling together, corresponding to fig. 14 in 
transverse section. 6, the folds, but not clinging together, i.e. the tubes which 
connect the cell-lumen with the continuous marginal tube, corresponding to 
fig. 15 transverse section. 


Figs. 21-22.—Triceratium Favus. 


Fig. 21.—One end of a section going nearly through the middle of a valve. 
a f, outer surface. if, inner surface. 7/, marginal ridge. x, portion where the 
section goes through the hexagonal prismatic chambers, consequently touching 
the chamber-openings £6. , portion of a section near the edge of a chamber, 
consequently the vertex shows a connection of the heads of the net-lines, 
d, spines in the angles between the hexagons. g 7, basal membrane. 

Fig. 22.Similar section, touching the middle of one of the three pro- 
tuberances. 


Figs, 28-8.—Coscinodiscus radiatus. 


Fig. 23.—Marginal portion of the middle section of a specimen at the moment 
of division (from the Norwegian coast). g7’, basal membrane of the original cell. 
g vr’, basal membrane of the valve in process of formation. g 0}, the girdle-bands. 
a s, the nodule of which mention is made in the text. pr, protoplasm. 

Fig. 24.—Marginal portion of a middle section through an undivided specimen. 
The letters have the same signification as in fig. 23. 

Fig. 25.—The first section from the series from which the preceding was 
taken; the girdle-band g 6 in surface view with the very small chambers of the 
margin r k. 

Fig. 26.—Small portion of the surface view of a specimen (from the mar] slate 
of Oran) focused to the plane indicated by line 1, fig.23. & 6, chamber openings. 

Fig. 27.—Similar portion with slightly lower focal adjustment, line 2, fic. 23. 

ne 28.—Portion of a specimen from the edge with abnormally thick chamber- 
walls. 
Fig. 29.—Coscinodiscus oculus iridis. 


Small portion of a vertical section. a f, outer surface, ¢ f, inner surface of the 
membrane. 
Fig. 30.—Coscinodiscus centralis. 


Portion of a section through a valve with unusually coarse marking. a f, 
outer surface; 4 f, inner surface. 
Fig. 31.—Coscinodiscus concinnus. 


Portion of a thin section; outer as well as inner surface can only be distin- 
guished at the common curve (not figured). 


Fig. 32.—Zupediscus argus. (Omitted.) 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 689 


PLaTEs X. AND XI. 
Figs. 33-52.— Achnanthes brevipes. 


mk, central node. 

ds, dorsal valve. 

vs, ventral valve. 

r 7, marginal ridge (r /’ old, r 7” young). 
g 6, girdle-band. 

s z, marginal view of the same. 


Fig. 33 x 670.—A chain consisting of two young frustules. The cell on the 
left is figured in full detail in the manner usually adopted in representing diatoms ; 
i.e. by focusing as a whole. The cell on the right is naturally similarly con- 
ditioned. The transverse lines are only indicated, but for the central part the 
highest focus has been chosen for the representation ; it brings to view the 
marginal strie s z’ of the old girdle-band. Further on towards the edge it is 
focused a little lower ; then only are seen the very short dotted striz s z’’ of the 
young girdle-band between the two marginal ridges. In the cell on the right, 
near one end, the young ridge has separated considerably more from the old 
one than at the other end. The numbers refer to the direction of the sections, 
figs. 40-2. 

Fig. 34.—The upper edge of the preceding fig. under exact medium focus. 
The marginal ridge shows a saddle-shaped depression, the small elevation is the 
young ridge in process of splitting away from the old one. The depression 
between the two must be looked upon as the first visible indication of the young 
girdle-band. The old girdle-bands extend one over the other only in the 
direction s. The cells are without doubt completely closed. The girdle-band is 
raised at the marginal ridge slightly. Marking of the surface view given with 
the valves below. 

Fig. 35 x 670.—A chain similar to the preceding, but a little older; the 
young marginal ridges r /” are further apart from the older r 7’. Only the stria 
of the young girdle-band s z” are represented. 

Fig. 36.—The upper edge of the left cell in fig. 35, in order to bring to view 
the relation between the two marginal ridges and the doubly thick membrane 
between them. 

Fig. 37 x 670.—An older cell, probably shortly before division. The peculiarly 
interrupted striated marking of the girdle bands is given. This is about the 
most complicated striation of all; between this and fig. 35 one finds all transitions. 
It seems as though the boxed-up girdle-band had already separated from its 
marginal ridge. 

Fig. 38 x 670.—A dorsal valve and 

Fig. 39 x 670.—A ventral valve viewed from the surface with full marking. 

Fig. 40 x 660.—Transverse section No. 1, 

ae % » 90, and 
pee 7 = aD 
out of a series of 23. They correspond to the dotted lines 1, 2, 3 in fig. 33 
(naturally with the modification that we have here to do with a chain of three 
frustules). Fig. 40, extreme marginal section which has touched only one 
portion of the lowest cell. Fig. 41, the middle cell partially injured in cutting. 
Fig. 42, the uppermost cell crumbled out. 
Fig. 43.—Transverse section No. 12 of the same series. The uppermost cell 
uite uninjured. Quite distinctly is here observable the difference in size between 
the old (r/’) and the young (r/") marginal ridge; the hook shape of the former 
also visible. The valve membrane is distinctly dotted (as expression of the dots 
between the transverse lines in the surface image). mr, mid-ribs, 

Fig. 44.—Portion of the same uppermost ceJl from the transverse section 

No. 9 of this series. The adjoining cell is split off whereby the duplex of the 
irdle-band becomes distinct, because in consequence of the fracture both mem- 
ranes have separated; gb’ the old, gb" the younger girdle-band. 

Fig. 45.—Portion of the ventral valve of this uppermost cell to show the mid- 
rib mr and the surrounding fine spaces as in the sections Nos. 8 and 16 of the 
above series. ‘The fine line q is the inner limit of one of the transverse stria. 


690 Transactions of the Sociedy. 


Fig. 46.—The dorsal valve of a cell with the cell-nucleus from the second 
transverse section series. 
Fig. 47 x 660.—Longitudinal section through a ventral valve in the direction 
of line 4, fig. 33. 
Fig. 48 x 660.—Longitudinal section through a dorsal valve in the direction 
of line 5, fig. 33. 
Fig. 49 x 660.—Section quite through the girdle-band in the direction of 
line 6, fiz. 33. : 
Fig. 50.—A portion of fig. 47, 
”» Le ” ” ’ 
”? 52.— ” ” 49, 
highly magnified. q, the ridge-sl.aped transverse lines projecting inwards. p, tl.e 
fine dots between them (? chambers). 


Fig. 53.—Synedra Gullionii. 
Any middle transverse section through a frustule. 


EXPLANATION OF THE PHOTOGRAPHS DEPOSITED IN THE 
LIBRARY. 


All photographs cxcept No. 12 have been made by me personally without 
eye-piece accurding to the old method with wet plates. No touching up has 
been done to any of them. No faults in the negatives are specially mentioned, 
but they can easily be distinguished from the objects used in demonstration. 

1. Pinnularia major; large specimen in balsam; a little more than half a 
valve. Produced by Schroder’s immersion 1/18 in.; x 631. 

The lines on the tracing paper covering the pl:otographs which can be con- 
nected by a ruler, indicate the direction of the sections in the space between 
a and 6 :— 


1 is the direction of the longitudinal section fig 5, photograph 3. 


2 a - 6, and portion of photograph 2. 
3 as transverse section 4. 

4 ” ” 1. 

5 ” ” 2. 

6 = oblique section, photograph 7. 

7 x transverse section of the valve m in plotograph 6. 


On the right-hand side the chamber openings are distinctly seen; in making 
line mr the median edges of these edges are t.uched; in the same manner Jr 
will touch the lateral edges. On the left and in other places on the valve the 
focus is nut so good, although both edges glimmer everywhere. 

From c to d is the region where presumubly the mid-rib shows the depression 
almost at right angles on the transverse section (fig. 3). From c¢ to the end- 
nodule ¢, and from d to the line 7, the mid-rib is simply a vertical incision (fig. 1). 
f, irregularly formed chambers on the right; the walls are here black and vanish 
at the lateral end. 

2. Pinnularia major. A coarser longitudinal section through two valves lying 
one in the other. Like all other following sections, so here the section is im- 
bedded in gum, the entire gum-chip surrounded by balsam. Position and 
mignification asin 1. The focus from a to } is the best; one sees in the valve 
on the right the transverse sections of the chambers with the inner membiane 
which closes the chambers; the section direction is approximately the sume as 
with line 2, photograph 1. In the valve on the left the opeuings are seen, but in 
consequence of the great thickness of the section the oblique ridge-shaped 
vertical chamber-walls glimmer and disturb the image, and which only becomes 
quite intelligible by photographs 3 and 7. In the lower part is a zigzag-shaped 
cleft r through the gum-chip; there the section is very thick and the focus 
unsuitable. This will convince us what errors can arise with a coarse object 
through mistakes in focus and cutting, and which in a less degree occur with finer 
objects like /’leurosigma. he valve on the right Las lost the outer membrane, 
which has apparently stuck on the gum on the right; the vertical chamber-walls 
are therefore toin off at the pont of connection with this outer wall, aud the 


The Structure of Diatoms. By Dr. J. H. L. Flégel. 691 


chambers erroneously suggest an outer opening. In the left valve these vertical 
chamber-walls appear on the inner side serrated (naturally, with both, the inner 
surface is on the left); this also is an optical delusion. In both valves the very 
dark walls are much thicker and more clearly expressed than in a reliable image; 
but the lumen of the chambers is reduced and strongly rounded off (also wrong !). 
The connection between the vertical walls with outer and inner membrane 
appears therefore like a thick nodule; whilst with good sections little can be 
traced of such end thickenings. 

3. Pinnularia major, Extremely thin longitudinal section exactly through 
the chamber-openings, focus and magnification as in 1. This is probably the 
best section in my collection, and can be recommended for all finer measure- 
ments. The best focus is from a to b; less good from 6 to c. The section 
direction runs in the line 1, photograph 1. One sees (best with the help of a 
lens) the club-like thickening of the chamber-walls; one can measure the 
thickness of the outer membrane, &c. The inner surface is on the right, proved 
by the bend in the section. On the left is a surface section of another valve. 

4. Pinnularia major. Collodion impression of the outer surface of a valve, 
in air. Produced by Schréder’s dry 1/6, x 298. The strongly black mar- 
ginal line is the expression of an elevation in the collodion originating in 
the same manner as we shall see when we come to photograph 5. The mid- 
rib is distinctly seen; it is a delicate ridge, corresponding to the cleft in the 
valve, and ends at the central nodule with a stronger point. The smooth space 
on both sides of the mid-rib slopes, beginning at that portion of the surface 
where the chambers are situated in the valve, and is there slightly different ; 
this difference probably originates by a change in the evaporation processes. 
Starting from the upper corner on the right we observe on the cast a chain of 
numerous small crystals of unknown origin (on the preparation itself). The lines 
on the left are Newton’s rings in the thin collodion film. All other dotting 
is the granulation of the collodion surface. 

5. Pinnularia major. Collodion impression of the inner surface of a valve. 
Produced as No. 4, same magnification. With regard to the general sketch of 
the valve the following is to be observed:—If in making a collodion cast of a 
valve (shown in fig. 119 as s) lying with its surface towards the slide (4), the fluid 


naturally fills up at first all the inner spaces. In hardening the mass contracts, 
and occupies afterwards as a solid film the shaded space c in the image. The 
quantity that originally entered into the angle between valve and glass thins 
away and appears as projection »; this accounts for the remarkable enlargement 
of the outline in the cast in comparison with that of the valve. Next to the so- 
formed dark surrounding edge follows an inner portion partly lighter, partly 
darker, and often interrupted. This is the depressed furrow in which lay the 
extreme edge of the valve (vide photograph 6), and had been so squeezed into 
the collodion that during the separation trom the valve many small fragments 
of this sculptureless edge remained behind in the furrow. On the surface 
one observes the impression of the central nodule, and further two longitudinal 
lines. These represent the collodion which ran into the chambers (vide text), 
and are raised ribs (#6 in the fig.). In several places are seen the threads 
described in the text. A part of this longitudinal line is drawn in fig. 7; 
conf. their description. (These raised ribs I have sometimes seen on casts 
of extremely small undefined Pinnularia ; one would otherwise only look for them 
in Navicula. The real details can only be learnt from large varieties.) On 
the left of the cast a large air-bubble had been enclosed in the collodion; 
near its centre we observe the granulation, elsewhere so distinct, decrease, which 
circumstance I have made use of for the explanation of the faint granulation 


692 Transactions of the Society. 


above the chambers on photograph 4. In the centre of the bubble Newton’s 
rings. The Stauroneis valve lying at the side is not free from the collodion. 

6. Pinnularia major. A number of exact transverse sections. Produced like 
No. 1, x 647. The section made after method I. is of exquisite thinness 
and flatness. It was photographed a few days after being made, therefore the 
little air-bubbles which ought to be formed in the chambers during the hardening 
of the gum are visible, whilst with other sections kept for some time they have 
been mostly absorbed by the balsam. Altogether transverse sections of twenty 
valves can be seen, and they are lettered A to U. Of A and B only portions are 
seen, but the others are entire. 

The focus on the left not very good; on the right chamber opening very fine; 
at the lateral edge of the same an oval air-bubble in the chamber. 

D, focus in the left not suitable; on the right median end of the chamber, 
and median edge of its opening fairly good; in the extreme lateral end of the 
chamber an air-bubble. 

E, similar section to M, but broken in the middle line; on the left median 
end of the chamber pretty good. 

F, broken up and useless. 

G, a tolerably good transverse section, a little broken up; chambers indistinct; 
mid-rib good; has the angle-depression of fig. 3. 

H, only good above; shows the fine pointing of the valve margin very sharp ; 
in it several air-bubbles ; lower down, broken up. 

I, quite similar. 

K, very beautiful section; chamber opening on the left is good, but not 
so distinct on the right; mid-rib is observable as a delicate cleft not quite 
through. 

L, similar section, mid-rib burst; on the left, chamber and its opening very 
fine; a few air-bubbles in the lateral end do not interfere much. 

M, one of the most magnificent sections, quite close to the central nodule 
(corresponding to the line 7 in photograph 1). The mid-rib is here an unusually 
deep vertical narrow cleft ; one sees the closing envelope very distinctly (with a 
lens); chamber of the upper half good, that of the lower indistinct, because only 
the partition-walls remain (like fig. 2). 

N, only the lower good, crushed at the top. 

O, central nodule section, hardly of use. 

P, useless. 

Q, apparently central nodule section, but injured ; focus unsuitable. 

R, focus unsuitable; the chambers can be recognized in outline. 

8, particularly beautiful, showing the mid-rib as a right-avgled bent cleft, like 
fig. 2; the chambers are tolerably good in the upper half. 

T, chamber of the upper half very good, also its narrowed lateral end; the 
mid-rib is broken, and the lower half useless. 

U, good section, but the focus not sharp ; both chambers visible. 

The section encloses a girdle-band section. 

7. Pinnularia major. Slightly oblique longitudinal section, produced like 
No. 1, x 650. This is another most elegant section in the direction of line 6 in 
photograph 1, and represents the end portion from line 4 to f. This, like 
photograph 3, is very suitable for all finer measurements under the lens. The 
following are chiefly remarkable :—In the region a the vertical division-walls 
thickened below between the chambers; the openings of the chambers; the very 
thin outer membrane. At the point 6 the lateral edge of a chamber opening is 
touched, and there appears in great strength the inner membrane (closing the 
ehamber below). At c, is a favourable image of a chamber lumen: the thin 
outer membrane, the more than twice as thick inner membrane, rounding off of 
the square transverse section of the lumen at the inner membrane. 

8. Hupodiscus argus. Middle section through a valve. Produced with 
Schréder’s 1/6 dry objective, x 298. On the left is observed the inner cavity 
in which is an air-bubble at the end. In the middle region is a faint indication 
of vertical chamber-walls. Spine-like points are observable on the lower outer 
surface of the valve, similar tu Ziiceratium spines. 

9 and 10. Pleurosigma balticum. Transverse sections, produced like 1, x 669. 
The section is made after method I. (in pure gum in collodion), and was photo- 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 693 


graphed a few weeks after. It is No. 76 out of 150 transverse sections. Through 
a number of 14-16 frustules, partly parallel, partly one on the other. Image 9 
was taken with somewhat higher focus, and image 10 with lower focus; the 
ditierence is naturally very insignificant. For the examination of these two 
images and of photograph 11 a lens should be used. For the representation of 
the sculpture my former description of the transverse sections of P. balticum 
should be referred to (6, pp. 481-5, figs. 13, 14 and 15). The separate frustules 
are marked A-L. For the comprehension of the arrangement of the frustules in 
comparison with photograph 11, we must observe that only the Pleurosigm A to 
D are in the original position, that the gum section on the right of D on account 
of extreme thinness is broken off, and that this broken-off and still further broken- 
up portion has fallen obliquely across the other portion which remained intact. 
The thinness of the gum-chip in this instance can be best estimated by noting 
that hardly any trace of the collodion limit lines can be seen (vide photograph 11), 
which must have existed below BK and D, About the separate sections the 
following is to be observed :— 

A, very thick section, kidney-shaped within. The left valve is broken in the 
middle, only the one half is seen. The right valve is broken up, but both the 
chief and secondary ribs, with a portion of thin membrane attached to the former 
distinctly visible; the chambers slightly indicated. 

B, a slightly tlinner section, strongly notched witlin. The left valve twice 
fractured; the right valve quite uninjured; only well focused in image 10; the 
tain membrane-stria next to the mi'-rib very beautiful; slight indication of 
chambers ; the girdle-band at the top is in normal position, below out of place, in 
photograph 10 clearly duplex. 

C, section thinner than B. Content wanting. The upper valve uninjured. 
Best focus in photograph 9; indication of chambers very good, particularly in the 
left half; a depressed furrow beside the mid-rib god, also the secondary rib, 
The lower valve is broken in the thin portion, although both halves are not much 
displaced. Focus in both images not exact. The left girdle-band is injured ; on 
the right clearly duplex; bvuth still adhere to their original valve, although 
slightly displaced one towards the other. 

D, this magnificent central nodule section, which forms the chief object of 
representation, and is rendered on a larger sale in photograph 12, I shall describe 
further on. 

E, injured section, only the lower valve good. The content adheres to the 
girdle-band. On the left a few fragments of valve transverse sections. 

F, a much injured section. The upper valve broken in two pieces, but the 
fracture is not in the thin membrane stria; the half lying a little higher shows 
in photograph 10 very good indications of chambers; the lower half to which is 
attached the content is not so good; tolerable in photograph 9. The lower valve 
broken up; the girdle-band has got out of place. 

G, imperfect section, which very clcarly proves what kinds of deception can 
take place in researches not conducted critically. In the half-valve on the right 
at the top one sees in photograph 9, without much trouble, the outlines of a base 
membrane, with ridge elevations noded at the ends. A little more imagination 
will add outer openings of the chambers. Photograph 10 destroys all these 
illusions, and proves at the same time that this section is much too thick for such 
studies; it is almost exactly the reduced copy of Pinnularia, photograph 2 at r 
(vide supra). 

11. Pieurosigma balticum, Everything like 9 and 10, except the transverse 
section No. 80 out of the same series (Nos. 77-8-9 were useless fragments 
cut through totally different portions of the bundle). This image chiefly 
serves to show that by using my section method the separate frustules can be 
identified from section to section, whereby real series of sections can be obtained. 
A to D can be easily recognized by comparing with images 9 and 10. Below 
B D E run two slightly bent parallel lines through the field of view; these form 
the limit of the transversely cut delicate collodion film on which the arrangement 
of the Pleurosigma took place. On the right of E the section is broken off and 
another gum-chip has fallen obliquely on it; the frustule sections H and I 
therefore lie one upon the other. For the separate scctions the following remarks 
may be serviceable :— 


694 Transactions of the Society. 


A, very thick and useless, in some places indications of chambers. 

B, scarcely better; the right valve has possibly a useful thinness, but is not 
distinct. 

C, has in the upper valve the deceptive image described above with G. 

D, the focus is tolerably good only for the lower valve, where at the same 
time is visible how the image of the central nodule transverse section passes over 
into the ordinary transverse section image. 

E, F, G, focus entirely wrong. 

H, shows specially the asymmetry of the secondary rib, exactly as I have 
described above (fig. 13). Indication of chambers in some places good. 

I, indistinct. 

K and L, two fragments of valve sections, the former showing the chambers 
very well. 

42. Pleurosigma balticum. The frustule D from the photograph10. Enlarged 
from the negative by means of the ordinary portrait objective. Total magnifica- 
tion, 2340. The image has been made, fearing that the delicacies of the negative 
during the printing would suffer considerably, and further to facilitate measure- 
ments. “The valve a’ is uninjured throughout, and gives an unblemished picture 
of the central nodule. The chambers disappear to the eye at some distance 
from the centre. Instead of the usual membrane-thinning commencing with 
mid-rib and secondary rib, the wall remains solid throughout (6’), but has two 
very small projections inwards (c’), between which is a slight depression. The 
chamber-walls are here distinct, the cavities dark ; the focus of photograph 9 is 
for this valve more advantageous. The valve a” is uninjured in the lower half, 
but the two projections c” of the central nodule are still visible; evidently here 
has been the extreme fine edge of the section. By comparing photograph 9 with 
it one detects faint traces of this lower half-valve, which we find again indicated 
in photograph 12. From the preceding we deduce that this section of the upper 
half-valve is sufficiently thin for the minutest investigations. The chambers are 
seen in full clearness and in such accordance with my former diagrams as if this 
preparation had served for them as model. The girdle-band g }’ is not quite 
distinct, in consequence of being crumbled; the other g 6” partly covered by the 
section of the frustule E. 

I have formerly given the greatest thickness of the cell-wall as 1°8. Con- 
sidering what is clear in the valve a’ and what is dark in a”, and that one must 
not reckon in a' the dark seam beyond the clear space, we get in this photograph 
the greatest thickness of the wall near the central nodule as 4-2 mm., consequently 


2 
the true thickness is =- =1'8y. The height of a chamber lumen may be 


estimated at 1/3 of this size; therefore these are all valves not beyond the power 
of microscopical observation. 

Valve E a belongs to frustule E, also the girdle-band E g 6 and the contained 
portion E 7. In the former is seen the indication of chambers tolerably well; the 
same may be seen in the valve fragment lying on the left. 

13 and 14. Triceratium Favus. Section No. 11 from a series of 19 vertical 
sections through a valve. Fig. 13 with high focusing; fig. 14 with low focusing. 
Produced with Seibert and Krafft's immersion VII. 6; x 652. The inner surface 
of the valve is turned downwards. 

15 and 16. Coscinodiscus radiatus. Middle section from a series of 31 vertical 
sections through a specimen in process of division. Produced like No. 1; 
x 660. Fig. 15, for the greater part of the section correct focus, especially reliable 
in the centre and a little lower. Here are the T-figures of the chamber-walls 
distinct, also the four base-membranes. Of less use is the lower end, although 
pretty distinct. For the upper end the focus is unsuitable. Image 16, gives the 
correct focus for the upper end, but not so well for the lower end; the middle is 
quite unreliable. At both ends is secn the overlapping of the thick girdle- 

ands. 

17. Triceratium Favus, Thin but not quite plane section. Produced like 1; 
x 680. The section direction is not exactly through the middle of the hexagons, 
therefore every pair of chamber-walls are brought closer and connected on the 
outer surface (on the left), and thus between each pair there is a slightly larger 


The Structure of Diatoms. By Dr. J. H. L. Flogel. 695 


space (a); here the outer entrance-opening is touched (6). The section is only 
thin enough and focused correctly at a. Below, near the marginal portion, 
another piece of diatom lying by accident on the valve has been touched. 

18. Surirella biseriata, Collodion cast in air. Production and magnification 
like photograph 4; it is the cast of the inner surface of a valve. The deep 
black edge is a raised collodion ridge, which is formed on the outer side of the 
wing as described above with Pinnularia. The distinct border next to it is a deep 
brown of the collodion; in it must have been the valve edge (figs. 13-17). The 
dark ribs on the surface are raised places, i. e. wave-elevations, the clearer inner 
spaces are depressions. At the lateral end of each wave-elevation, not far from 
the distinct marginal line, is a dark dot. In the cast is a vertical projection; 
these thorn-like spines naturally are the contracted outlets of the channels. In 
the mid-:ib a stria of the valve has remained behind. Collodion surface remark- 
ably smooth. 

19 and 20. /sthmia enervis. Two successive sections, Production asin1; x 633. 
The one section must be adjusted to the other like a mirror image. The separate 
sections are A, B,C. The situation of the cells in the gum has unfortunately not 
been figured before cutting, and it is now almost impossible to define them; but 
so much is certain, a few sections further on A and B coalesce, consequently both 
belong to one cell, whilst C is a second cell, apparently touched nearly trans- 
versely. B is therefore, as its small extent teaches, doubtless a section through 
the extended end of the rhomboidal cell, either through a free corner or more 
probably through the isthmus proper. This is here important. 19 is a very thick, 
20 is a very thin, section in which the isthmus section is a little injured; the 
section of the cell C is flapped over at the top or pushed together. In both 
sections one sees in the ring B on the inner side ridge-projections, which are the 
cause of the well-defined cell-marking. Had I given this with only one section, 
some severe critic might have retorted that the ridges might be on the outer side, 
and that the apparent inner projections were obliquely struck in projecting 
marginal portions. Such like opposition is refuted by the image of the second 
section. Designating here the projections, for example, 1, 2, 3, &c., one will find 
that all fit exactly one to another except that, instead of No. 3, photograph 20, 
we see two projections standing close together in photograph 19, evidently because 
here in the first instance an areola corner was touched. This comparison proves 
further, that the membrane was touched exactly vertically by the section on the 
right side in photograph 19 (or on the left in photograph 20), but on the opposite 
side obliquely. The more reliable thinner section 20 proves undoubtedly the 
turning-in of the ridges and the outer smoothness of the membrane. 

The section through the cell C is by far too thick for the study of the 
sculpture. In section A are found a few places in photograph 19 (just below the 
middle), where it has the required thinness for the observation of the very thin 
ridges on the outer side of the membrane. Judg ng from the numerous examples 
of these images in other sections I cun only declare it to be the girdle-band. 


BIBLIOGRAPHY. 


1. Aspe, Prof. E—Beitrage zur Theorie des Mikroskops und der mikrosko- 
pischen Wahrnehmung. Arch, f. Mikr. Anatomie, ix. pp. 413-68. 

2. Dexy, F.—Note sur Vargile des Polders suivie d’une liste de fossiles qui y ont 
été observés dans la Flandre occidentale. Annales de la Société Malaco- 
logique de Belgique, xi. 1876. 

3. Dirre, Prof, L.—Beitrage zur Kenntniss der in den Soolwassern von Kreuz- 
nach lebenden Diatomeen, sowie iiber Structur, Theilung, Wachsthum 
und Bewegung der Diatomeen iiberhaupt. Kreuznach, 1870. 

4, EnGeLmAnn, Prof. Ta. W.—Neue Methode zur Untersuchung der Sauer- 
stoffausscheidung pflanzlicher und thierischer Organismen. Botanische 
Zeitung, 1881, pp. 441 et seq. 

5, Fioce.—Ueber optische Erscheinungen an Diatomeen. Bot. Zeitung, 1869, 
pp. 713, 729, 753. 


696 Transactions of the Society. 


6. 


7. 


8. 


F.Lé6cEeL.— Untersuchungen iiber die Structur der Zellwand in der Gattung 
Pleurosigma. Arch. f. Mikr. Anatomie, vi. pp. 472-514. 

— Ueber die Structur der Diatomeenschale. Tageblatt der Versamm- 
lung deutscher Naturforscher und Aerzte zu Leipzig, 1872, p. 141. 

— Ueber die quergestreiften Muskeln der Milben. Arch, f. Mikr. 
Anatomie, vill. pp. 69-80. 

Die Diatomaceen in den Grundproben der Expedition zur Unter- 

suchung der Ostsee. Bericht der Pommerania-Expedition, pp. 85-95, 

1883. 


. Hatiier.—Die Auxosporenbildung bei Cymbella gastroides Kiitz. Zeit- 


schrift, Humboldt, April, 1882. 


. Just, Prof.—Botanischer Jahresbericht 1873, &c. 
. LevcKart, Prof.—Die menschlichen Parasiten und die von ihnen herriilr- 


renden Krankheiten. Ite Aufl. 1863. 


. Morenouse, G. W.—Silica Films and the Structure of Diatoms. Monthly 


Microsc. Journal, xv. p. 39. 


. Miter, Orro.—Untersuchungen iiber den Bau der Zellwand von Triceratium 


Favus Ehr. SB. der Gesellschaft naturforsch. Freunde zu Berlin vom 
17 October 1871, pp. 74-81. 


. —— Ueber den feineren Bau der Zellwand der Bacillariaceen, insbesondere 


des Triceratium Fayus Ehr., und der Pleurosigmen. Reichert’s und Du 
Bois-Reymond’s Archiv, 1871, pp. 619-43. 


. —— Ueber den Bau der Zellwand der Bacillarien-Gattung Epithemia Kitz. 


SB. der Gesellschatt naturforsch. Freunde zu Berlin vom 15 October 1872, 
pp. 69-71. 


. NAGELI und ScHWENDENER, Profs.—Das Mikroskop. Theorie und Anwendung 


desselben. 2nd ed. 1877. 


. Privzer.—Ueber den Bau und die Zelltheilung der Diatomeen. Bot. 


Zeitung, 1869, p. 774. 


. —— Untersuchungen iiber Bau und Entwicklung der Bacillariaceen 


(Diatomaceen). Botanische Abhandlungen von J. Hanstein, i., 2, pp. 1- 
189. 1871. 


. — Die Bacillariaceen (Diatomaceen). In Encyclopaidie der Naturwissen- 


schaften, Handbuch der Botanik von Prof. S:henk, 1882, ii. pp. 403-45. 


. Prinz, W.—Etudes sur des coupes de Diatomées observées dans les lames 


minces de la roche de Nykjobing (Jutland). Ann. de la Société Belge de 
Microscopie, vii. 18 0. 


. Rasennorst, Dr.—Flora europea Algarum aque dulcis et submarine. 


Sectio I. 1864. 


. ScHumann, J.—Die Diatomeen der hohen Tatra. 1867. 
. Scouttze, Prof. M.—Die Bewegung der Diatomeen. Arch. f. Mikr. 


Anatomie, i. pp. 376 e¢ seg. 1860. 


. Stack, H. J.—On the structure of the valves of Hupodiscus Argus and 


Isthmia enervis, showing that their siliceous deposit conforms to the general 
plan of deposition in simpler form. Monthly Microsc. Journal, viii. 
(1872) p. 256 ; i. pp. 123, 186. 


. SrurHENson, J. W.—Observations on the optical appearances presented by 


the inner and outer layer of Coscinodiscus, when examined in bisulphide of 
carbon and in air. With 1 plate. Monthly Microsc. Journal, x. p. 1. 


. SvRasBuRGER, Prof. E.—Ueber den Bau und das Wachsthum der Zellhaute. 


Jena, 1882. 


. Weiss, Prof.—Zum Baue und der Natur der Diatomaceen. SB. der k, Acad. 


der Wissenschaft, I. Abth. 1871, Feb., pp. 1-37. 


. Weis, S.—The structure of Zupodiscus Argus. With 1 plate. Monthly 


Microse. Journal, ix. p. 110. 


C 69% <) 


XVIL—On Drawing Prisms. 
By J. AntHony, M.D. Cantas., F.R.C.P., F.R.MS. 
(Read 11th June, 1884.) 


Wen the scientist is investigating matters of special interest by 
means of the Microscope, he naturally wishes to record pictorially 
what he sees, and particularly if the objects under examination 
should chance to be of a perishable nature. If he has not under- 
gone some sort of artistic training, his efforts with the pencil will 
generally fail lamentably to convey an idea of what he sees in the 
Microscope; his drawing will probably be utterly wanting in 
“character,” and his outlines poor and uncertain—shortcomings 
which he will probably try to make up for by a painful elaboration 
of detail. This is not altogether a fancy picture. A man may 
have a most intense and learned appreciation of what the Micro- 
scope reveals to him, and yet be utterly unable to make a reliable 
sketch, much less a picture. It is under such circumstances that 
inventive brains have been stimulated to devise appliances which, 
placed upon the eye-piece of a Microscope, should, by well-known 
laws, project the Microscopic image on to a blank sheet of paper in 
front of the observer, who would be enabled to trace with the point 
of a pencil the outlines and salient points of the shadowy micro- 
scopic image. 

This is, of course, a very rude description of the general action 
of all the mechanical aids to drawing from the Microscope, but 
further on we shall see that special means have been devised to 
attain special ends. 

Three questions have repeatedly been put to me. 

1. What is the special advantage of using a drawing prism ? 

2. Does it require a knowledge of drawing to use it ? 

3. What form of prism will be the best to employ ? 

The answerto the first question is easy. The employment of 
a prism means an enormous saving of time, and not only that, but 
used with simple precautions, it means the power of delineating 
with almost rigid accuracy the outline of all objects seen in the 
Microscope. And this is not all the advantage, for an absolutely 
identical magnification can be insured in every successive drawing 
by simply marking on the Microscope a fixed observing or sketching 
angle, and by using for successive sketches the same objective and 
same ocular duly armed with the prism. As each drawing is com- 

leted, a simple substitution of a micrometer on the stage of the 
nasa allows a “scale” to be projected on to the drawing, or 
on the side of it, which may be thus said to have received its 
official stamp. 

Ser. 2.—Vo, IV. 3A 


698 Transactions of the Socvety. 


To reply to the second question :—Most assuredly no special 
knowledge of drawing is needed for making accurate outlines 
with the aid of a prism; little more than the first lesson in free- 
hand drawing is required, viz. the power of tracing lines with 
firmness and certainty of touch. 

The third question, as to the best form of prism, will be met 
by a short review of the various forms of drawing appliances from 
the days of Wollaston, who devised a prism which in many of its 
qualities has never been surpassed. In making such a review this 
evening, as I shall have to “name names,” it need hardly be said 
T shall strive to keep within the bounds of fair criticism, and 
especially to eschew invidious comparisons. Time would not allow 
me to go into the optical construction of the various appliances 
which I shall have to bring before your notice ; all these particulars 
can be learned from the back numbers of our Journal. I prefer to 
take these little adjuncts to the Microscope just as they were sup- 
plied to me by their more or less sanguine inventors, and to narrate 
what they have respectively done in my hands, premising a hope 
that as I have had one or the other in pretty constant use for some 
forty years, a description of their performances will neither be 
unwelcome nor unprofitable to the practical microscopist. 

In illustration of the remarks I have to make, and as showing 
the various applications and “all round ” character of the drawing 
prism—and particularly in its more recent forms, I venture to 
exhibit selections from among the thousands of drawings I have 
made, choosing those which may be said to be typical of the uses 
of the prism. 

The subjects are, as you will see, of all sorts, but having this in 
common, that they were all drawn under the Microscope; all out- 
lined by the prism. When you see copies from photographs, from 
book-illustrations, magnifications of the exquisite engravings in 
Yarrell’s ‘British Birds,’ and Bell’s ‘Reptiles’—such as the 
venomous and non-venomous snake—and proceed from these low- 
power magnifications through the whole range up to the delinea- 
tions of living diatoms as seen with my grand Tolles 1/25 objective, 
I think you will feel an incipient respect for the use of the little 
instrument, the use of which I advocate. Just let me call 
attention to the important fact, that in each rapidly executed copy 
of an engraving, every mark of the graver’s tool has been indicated 
at one operation by pen and ink while still under the Microscope ; 
and in mere outlines of microscopic objects—whether executed with 
pen or pencil, all have been purposely left as they were traced under 
the instrument ; or to use other words familiar to drawing academies, 
they have not been “tcuched up.” 

Ag an example of the satisfactory character of this untouched 
outline, I hand round copies of the well-known Plewrosigma 


On Drawing Prisms. By Dr. Anthony. 699 


angulatum, as executed with various prisms, the sketch of each 
having occupied as nearly as possible half a minute! Those who 
have sketched P. angulatum will be conscious that several minutes 
are generally needed to get the peculiar curves of this diatom 
satisfactorily. Here are many outlines made in succession of this 
same lorica, to show how identical they all are in character. The 
large drawing or diagram of some well-known forms of diatoms 
is a tour de force, and here the effect would be better, or easier 
got, by copying some moderate-sized prism outlines, by means of 
the pantograph ; but the drawing as it stands really was executed 
under the Microscope; the paper was laid on the ground with a 
bright light thrown upon it, the Microscope was well raised over the 
edge of the table. The image—enormously amplified—got from 
a 1/6 objective, was projected by the prism, and was traced upon 
the paper by the aid of a pencil ; which pencil might be said to be 
some 5 feet long, inasmuch as it was formed by a crayon tied 
firmly on a joint of a fishing-rod. ‘That the outline so traced was 
a bit “shaky,” and needed “ mending” may well be imagined, but 
the reparation has, I think, not been made at the expense of the 
characteristic curves of the various diatoms. I am sure the relative 
size of each may be depended on, though I must own to depicting 
the largest and boldest specimen of P. angulatum I could lay my 
hands on. 

After this much of preamble, permit me to name the various 
forms of drawing appliances or prisms from which to make a 
selection ; all of them have some merit, and some of them, as I 
trust I shall be able to show, are pre-eminently useful. First 
come “steel disk” or “ neutral-tint” glass reflectors; then prisms 
proper, by Wollaston, Gundlach, Beck, Oberhauser, Zeiss, Nobert, 
Abbe, Nachet, and Schréder. They may be classed thus, 
Wollaston, steel disk, and glass reflector can only be used when the 
Microscope is placed horizontally—a position which is always a 
more or less cramped one for the observer, and which is all but 
impossible to adopt in connection with dissections, and indeed with 
most objects mounted in fluid and more or less free to move in the 
cells. The prisms of Beck, Gundlach, Zeiss, and Schréder are avail- 
able when the Microscope is set at the usual observing angle. 
The prisms of Oberhauser, Nobert, Abbe, and Nachet can only 
be employed when the Microscope is placed in a vertical position ; 
the image is projected a few inches to the right-hand side of the 
Microscope, and falls on a sheet of paper fixed to a 2 ft. drawing 
board, so that tle point of a peasit which is held in the right 
hand, is in a convenient position to trace the outline of the 
projected image. 

I will now proceed to describe the special qualities which some 
of these prisms have as adapting them for particular purposes. 

3A 2 


700 Transactions of the Society. 


The “reflectors” and the “Gundlach” will be found in use to 
“invert the image”; this inversion is very troublesome, and if not 
well understood, and met with certain devices, is apt to lead the 
draughtsman into endless confusion. In practice when you use 
one of these inverters you are compelled to sketch from the one 
side of a slide of objects, and to fill in detail from the other, and as 
a clever writer has pointed out with respect to this arrangement, 
“the back and the front of an object are not always alike.” 

The image got by a Wollaston prism is so excellent that this 
instrument would always be used, were it not that the setting of the 
Microscope in a horizontal position, the re-arrangement of the 
light, &c., the dependent position of the eye while drawing, the more 
or less cramped position, and other difficulties with respect to the 
slipping of fluid preparations oblige one to employ more convenient 
though perhaps in other respects less satisfactory appliances. Of 
the prisms used at the ordinary observing angle of the Microscope, 
Gundlach’s, as I said, inverts the image, and I am sorry to say that 
the Zeiss prism, though it is quite satisfactory in my hands, in , 
most respects, projects the image so far forward as almost to come 
upon the stand of the Microscope, and so practically cramps the 
position of the drawing paper or board; I therefore seldom use 
it. I lke the Beck prism, and I make perhaps more use of it 
than of any other, as the light transmitted, the field, and the sight 
of the pencil are all satisfactory. 

The Schroder prism just invented has several points of 
excellence, which will win appreciation. It shares with the 
Wollaston the rare quality that the pencil is seen with equal 
distinctness in all parts of the field, and that there is no apparent 
change in the position of the point of the pencil from imvolun- 
tary oscillation of the head of the draughtsman. I am only sorry 
to be obliged to say, that I find the usefulness of this neat 
little instrument is much limited by the very small amount of light 
it transmits from the object under the Microscope; entailing the 
condensation of such a body of light by ‘‘racking up,’ when 
anything like a high power objective is used, as rather to strain 
the vision and make anything like detail too much a matter of 
guess. I am encouraged to hope that this condition may be 
susceptible of modification, and in such case the Schréder prism 
would not leave much to be desired. 

I may just say, that while not appreciating the Abbe prism 
used for the purpose for which it was constructed, I recognize a 
most valuable quality which it possesses, for copying drawings and 
engravings of small area, either of the size of the original or with 
a slight magnification at will. I think I can see a considerable 
future for this prism in certain branches of the fine arts. 


On Drawing Prisms. By Dr. Anthony. 701 


For the Microscope placed vertically, I will only call attention 
to one drawing appliance, viz. the “ Nachet hooded prism,” which 
you will see I have placed on the ocular of a Microscope in the 
usual position for sketching. Looking through this prism the 
image in the Microscope will be seen projected some 5 in. on to 
the drawing-board placed on the right-hand side. As a prism 
this has all the advantages and the faults of the class to 
which it belongs; a very prominent fault being the all but total 
loss of sight of the image of the pencil when an attempt is made 
to follow the outline of an object seen between the centre and the 
outside edge of the field of view—calling the outside that which is 
apparently farthest away from the microscope-body. 

If the drawing-board is placed flat upon the table, you will find 
that your drawing so made by the Nachet will be much distorted. 
A good article in our Journal * set me off to experiment on this 
distortion, and how to get rid of it. I show the satisfactory results 
arrived at. The boy’s head—a cutting from ‘ Punch ’—has been 
copied twice, in the left-hand picture the drawing-board was flat 
upon the table. The eye will detect the distortion in a moment, 
in the head being far too deep from front to back. The right- 
hand image—taken with the board raised 2 in. at its right-hand 
end—shows not a trace of distortion. Here is a still more severe 
test: these (fig. 120) are copies of the circles in Méller’s smaller 


Fic. 120. 


“typenplatte” under the same conditions as to position of drawing- 
board. The right-hand picture is shown by the dotted circle struck 
by the compasses to have lost the distortion, which is painfully 
evident in the one on the left-hand side. 


* Vol. ILL. (1883) p. 560. 


702 Transactions of the Society. 


In this drawing (fig. 121) of the lines of a fine stage-micro- 
meter, with drawing-board horizontal and inclined, all appreciable 


Fig. 121. 


distortion has been got rid of by the simple device of raising 
the right-hand extremity of the drawing-board. Well, this dis- 
tortion being eliminated, and the loss of sight of the pencil under 
certain conditions condoned, we must recognize this prism of | 
Nachet as being exceedingly useful and convenient in practice, it 
being so hinged upon the collar which clasps the ocular, that the 
optical part can be thrown back like a hood, so as to give a clear 
view of detail through the ocular only, and the prism can be tilted 
forward again at will to resume the sketching of outlines with no 
fear of loss of coincidence with its former position. A tinted glass 
which can be interposed between the object and pencil respectively, 
helps to make the Nachet hooded prism a great favourite of mine. 

Speaking of this “light-moderator” brings me to the point 
that one of the great secrets of success in prism drawing from the 
Microscope is the equalization or balancing of light from object 
and pencil. The best effect by far is got by two lamps. Where 
light from the paper is too glaring, as will often happen with 
the Schroder prism used in daylight, the half-shadow of a curtain 
allowed to fall upon the paper conduces wonderfully to ease in 
sketching. I have intimated that with the Schréder prism you may 
move your head as much as you like, but not so with the other 
little optical appliances, and this keeping the head steady is as 
difficult as it is wearisome. Failing an appliance something like 
a photographer's “head-rest,” let me suggest a substitute in a 
microscope-box, in the position that the left elbow can rest upon it, 
when the outspread thumb and fingers placed against the forehead 
will be found to keep the head of the draughtsman fairly steady. 
A small black velvet curtain, so hung ag to touch the microscope- 
tube just below the ocular, will be found to aid materially in 
distinctness by cutting off diffused light. You want to see all you 
can of your object, but make up your mind you will never see 


On Drawing Prisms. By Dr. Anthony. 703 


anything like the amount of detail through a prism which you do 
through the unarmed ocular. 

My conviction then is, that the prism has done very much—and 
indeed all it can do—in enabling you to get rapidly and correctly 
as a sketch the outlines and salient points of your object under 
examination, to which your more or less artistic eye will have to 
supply the detail. 

Now to sum up the evidence for the most useful forms of 
prism :— 

At the usual observing angle of the Microscope, and when the 
object is fairly transparent, Beck or Schréder will do good work, 
but where there is opacity, then Gundlach is to be preferred, in 
spite of its inverting the image. 

When the Microscope can be placed horizontally, and the 
objects are suitable, Wollaston’s prism gives results of pre-eminent 
beauty. 

With the Microscope vertical, Nachet’s hooded prism, I think, 
stands alone for making copies of almost all objects susceptible of 
magnification, and it is especially good when dissections are made 
under the Microscope by aid of an “rector,” as the convenient 
tilting backwards and forwards of the prism 
allows outlines to be traced, and then dis- Fig, 122. 
section to be resumed with the most charming = 
facility. 

This review of prisms has been a mere 
outline, but it has taken up all the time I 
could venture to occupy. While striving to 
criticize fairly, and placing most stress upon 
practical points, I have ventured to show 
what a long and assiduous use of the prism has effected in my 
hands: permit me to end with the hope that it may do still more in 

ours. 
N.B.—Fig. 122 is a woodcut of the Beck prism, which I 
believe has not previously been figured. 


704 SUMMARY OF CURRENT RESEARCHES RELATING TO 


SUMMARY 


OF CURRENT RESEARCHES RELATING TO 


ZOOLOGY AND BOTANY 


(principally Invertebrata and Cryptogamia), 


MICROSCOPY, &c., 


INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* 


ZOOLOGY. 


A. GENERAL, including Embryology and Histology 
of the Vertebrata. 


Embryology of the Sheep.j —Dr. R. Bonnet has investigated the 
earlier stages of development in the sheep embryo. 

His positive results commence from the twelfth day after impreg- 
nation. Embryos of this age showed round, uniformly bilamellar, 
germinal vesicles, with a round, bilamellar, embryonic disk of about 
-25 mm. in diameter. The epiblast of the disk consisted of two or 
three layers of cylindrical cells continuous with the flattened ecto- 
blast of the vesicle. The entoblast formed a single distinct layer of 
cells, distinguishable into two classes, according to position, viz. :— 

1. Ovoid cells, beneath the disk. 

2. Flat cells, forming a retiform membrane, lining the vesicle 
generally. 

The ovoid cells form “the entoblast of the (future) digestive 
tract,” the flat peripheral cells “the entoblast of the yolk-sac.” 

On the thirteenth day there appears in the vesicle, peripherally 
to the disk, a formation of mesoblast in the vesicle. No trace of such 
a mesoblastic growth is found at this stage in the disk. 

Within the disk, mesoblast is formed a little later in a twofold 
manner. Beneath what eventually is the primitive groove there is 
formed an ectoblastic “thickening” (Knoten). From this is developed 
the “central” or “ectoblastogenous” mesoblast, which remains in 
direct and intimate connection with the ectoblast axially. The 
“peripheral ” or “‘ entoblastogenous” mesoblast arises as a peripheral, 


* The Society are not to be considered responsible for the views of the 
authors of the papers referred to, nor for the manner in which those views 
may be expressed, the main object of this part of the Journal being to present a 
summary of the papers as actually published, so as to provide the Fellows with 
a guide to the additions made from time to time to the Library. Objections and 
corrections should therefore, for the most part, be addressed to the authors. 
(The Society are not intended to be denoted by the editorial ‘‘ we.”) 

+ Arch. f. Anat. u. Physiol. (Anat. Abtheil.) 1884, pp. 170-230 (3 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 705 


lenticular thickening of the entoblast of the digestive tract, and its 
cells wander or are thrust in, centripetally, to meet the centrifugal 
growth of the ectoblastogenous mesoblast. Very soon, however, the 
production of entoblastogenous mesoblast is observed to take place, not 
merely at the periphery, but over the whole surface of the entoblast 
of the digestive tract. Dr. Bonnet concludes that the cells of the 
mesoblast are to be regarded as mesenchyma in the sense of the 
Hertwigs. 

The primitive thickening of the ectoblast grows caudally to form 
the primitive streak, whilst the primitive concavity which is hollowed 
out in it elongates caudally in a similar manner to form the primitive 
groove. 

By the fourteenth day there is a cranial process of the primitive 
streak, the first “ rudiment of the ectoblastogenous chorda.” 

The formation of the ccelom in the sheep commences peripherally 
from the disk in the outlying tract of mesoblast, and progresses 
centrifugally, its proximal limit being formed by the very distinct 
mesoblast-forming border of the entoblast of the digestive tract, now 
underlying the growing disk. 

The author has found a canal piercing the cranial process of 
the primitive streak, and placing in (temporary) communication 
(1) the surface of the epiblastic thickening from which the neural 
canal is later formed, and (2) the digestive cavity. This canal he 
identifies with Balfour’s neurenteric canal. 

The first beginning of the blood-vessels was discovered in the 
proximal region of the coelom, external to the embryo, and was seen 
to arise contemporaneously in both layers of the mesoblast at this 
point, developing centrifugally at a later period. As both layers of 
mesoblast are, according to Dr. Bonnet, entoblastic, arising in the 
first instance at the border of the entoblast of the digestive tract, 
there is proof of the “indirectly entoblastic origin of the rudiments 
of the blood-vessels.” 

Dr. Bonnet promises a further paper on the further development 
of the sheep’s embryo. 


Development of the Generative Organs.*—O. Cadiat has an 
important memoir on the development of the generative organs in the 
embryos of the sheep and of man. The results are as follows :— 

The internal always appear before the external generative struc- 
tures. The cloacal cavity, which is formed early, commences to divide 
in embryos of 8 mm. long into an intestinal and genito-urinary portion ; 
but at the lower end of embryos of this age the two are still in com- 
munication. When the embryo has attained to 1 cm. in length the 
separation has advanced somewhat further back, but at the level of 
the caudal extremity there is always a small common cloacal cavity. 
In embryos a little older (12 mm.) the genital become partly sepa- 
rated from the urinary passages; it is not until much later (embryos 
of 6-7 cm.) that the separation between the intestinal, genital, and 
urinary tubes is complete. 


* Journ. Anat. et Physiol., xx. (1884) pp. 242-59 (4 pls.). 


706 SUMMARY OF CURRENT RESEARCHES RELATING TO 


The prostate glands are stated by Kolliker to make their appear- 
ance at about the third month in the human embryo; in reality, 
they appear somewhat earlier, about the second month; in a 
previous investigation carried out in conjunction with M. Robin, it 
was found that the prostate glands form a system entirely inde- 
pendent of their ducts and of the ejaculatory canals; and the present 
research confirms this idea; the prostate also is not connected 
with the urinary apparatus, as it was said to be by Virchow, but 
with the genital system; it is comparable to the glands of the 
urethra in the female; the entire urethra in the female is conse- 
quently homologous with the prostatic portion only of the male 
urethra, while the penial portion, including Cowper’s glands, cor- 
responds to the vulva in the female. = 

The external genital organs are fully formed at a somewhat 
earlier date in the male than in the female; at three and a half 
months they are very nearly complete in the male, while in the female 
at this period there is still a slit uniting the urethra with the vagina ; 
a complete separation is accomplished after four months. 


Spermatogenesis,*—MM. Swaen and Masquelin have published 
their very interesting observations on the developmental history of 
spermatozoa, in continuation of the work of Lavalette St. George. 
To understand the work of the later observers, it is necessary to 
recapitulate St. George’s conclusions. They are as follows :—Sper- 
matozoa originate in special cells, very similar to young ovules, 
which may be called spermatogonia. These elements multiply and 
form groups of small cells, spermatocytes, which remain grouped 
together so as to constitute <permatogems. At the periphery of the 
spermatogems a certain number of spermatocytes are modified so as 
to form a membranous envelope, a cyst (amphibians and insects). 
In other cases (Selachians), a single spermatocyte is modified at the 
base of the spermatogem and forms the basilar cell. In mammals, 
on the other hand, the spermatogem developes neither a cystic 
membrane nor a cystic basilar cell. Itis the spermatocytes which 
are transformed into spermatozoids. 

In addition to these elements there occurs a second kind of cell, 
forming a more or less complete envelope for the spermatogonia. 
These follicular cells play only a very secondary part in sperma- 
togenesis, eventually disappearing. 

MM. Swaen and Masquelin conducted their researches on the 
testicles of Scylliwm catulus, the salamander, and the bull. 

In Scyllium, the seminiferous ampulle of the testicle (cf. Graafian 
follicles) contain groups of two kinds of cells, (1) the central sper- 
matogonium or male ovum, a large nucleolo-nucleate cell partly in 
contact with the adjacent connective tissue, partly bounded by (2) the 
smaller, oval or irregularly shaped, follicular cells. As the “male 
ovule” multiplies (by indirect cell-division), the follicular cells also 
multiply and force their way inwards between the resulting daughter- 
cells of the spermatogonium to finally form a bilamellar body 


* Arch, de Biol., iv. (1883) pp. 749-802 (5 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 707 


composed peripherally of the latter cells and internally of the 
follicular cells. 

The two classes of cells remain throughout perfectly distinct, and 
Semper is mistaken in thinking that male ovules can be formed from 
follicular cells. 

Cell-division of the male ovules eventually forms bicellular columns 
of radiating cells. These columns are the spermatogems, of which 
the component cells are the spermatocytes. Each spermatogem is 
proximally capped with a follicular cell, generally crescent-shaped. 
When each spermatogem consists of six cells this follicular cell 
makes its way centrifugally between the columns, and attaches itself to 
the distal end of the spermatogem as the so-called “ basilar nucleus ” 
(really a complete and distinct cell). 

When this stage has been reached, the remaining follicular cells 
atrophy and further multiplication takes place in the spermatocytes, 
the resulting rows of cells (nematoblasts) arranging themselves with 
reference to the axis of the spermatogem (or nematogem, as it may 
now be called) much as the plumules of a feather with reference 
to the rachis. 

A caudal cavity is now formed internally in each nematogem, 
and into this space protrude the “tails” of the resulting spermato- 
zoids. The nematoblasts in their development become rectilinear, 
and their distal ends eventually form a parallel series, capped by the 
basilar nucleus. The head of the nematoblast is composed both of 
nucleus and of cell-protoplasm. The appearance of the nematogem 
is that of a cone of tapering filaments. 

As regards the “ problematic body,” nothing new was observed. 

Eventually the basilar nucleus forms a simple tube surrounding 
the “sheaf” of spermatozoids, and it is probably by its contractions 
that these latter are finally expelled. 

In the salamander the ampulla show a cavity, and the follicular 
cells form an investment for the male ovules. Multiplication and 
other phenomena occur much as in Scylliwm. 

In mammals the true male ovules are the small parietal cells 
considered as follicular by Lavalette. These male ovules behave in 
mammals much as their counterparts in Selachians, &c., except that 
of the two first products of their division, the one remains inactive 
for a certain time (inert male ovule), whilst the other (active male 
ovule) multiplies by division toformaspermatogem. This peculiarity 
of mammalian spermatogenesis is due to the continuous production 
of spermatozoids in the same seminiferous tube. 

In conclusion, MM. Swaen and Masquelin institute the following 
conclusion between cell-development in testicle and ovary :— 

1. In the ovary, the ovule little by little assumes considerable 
proportions, the follicular cells multiplying actively to form a con- 
tinuous envelope, and in some cases to effect the expulsion of the ovule. 

2. In the testicle, the ovule forms a number of little cells which 
eventually become spermatozoids. The follicular cells multiply to 
only a slight extent; more commonly they increase in size (Sela- 
chians and salamander). 


708 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Factors of Sexuality.*—K. Diising commences by discussing the 
correlation of the organs, and reminds us of the familiar fact that 
agriculturists are in the habit of removing the genital organ from 
those individual cattle that they wish to fatten. It is next pointed out 
that in nearly all cases where organs disappear, as for example in 
parasites, the reproductive apparatus is always retained, while, on the 
other hand, in sterile hybrids there is a marked development of the 
organs which preserve the life of the individuals. 

With regard to the proportional relations of the sexes, we have some 
statistical observations; to these the author now adds some consider- 
ations from the point of view of the doctrine of natural selection, and 
he points out that the numerical supremacy of one sex may be of 
considerable advantage in the development of a large progeny. He 
thinks, further, that it is possible to demonstrate mathematically that, 
where there is an abnormal relation of the sexes, an animal which 
produces a large number of the kind of individuals that are wanting 
will leave more descendants than one that does not do so. This 
peculiarity will, in time, be confirmed by natural selection. In 
illustration of this reference may be made to what seems to be a 
statistical truth ; late fertilization of women tends to the production 
of males, and, in all circumstances, the first-born are, in the majority 
of cases, boys. Further, the author believes that statistics show 
that after a war there is a large preponderance of male babes. 

Where, among cattle, demands are largely made on an individual 
bull, the majority of his progeny are males, and this is because young 
spermatozoa tend to produce males; this view of the different value 
of spermatozoa of different ages has the support of so high an authority 
as Prof. Preyer. Reduced to a general law, the results may be thus 
enunciated: the larger the want of individuals of one sex, the more 
frequently are their genital products required, and, therefore, the 
more frequently do the minority produce young of their own sex. 
The investigations of Thury have shown that young ova tend to form 
progeny of the female sex, while delayed fertilization leads to the 
production of males; the calves of the earlier stages of the rut are 
more frequently females than those of the later. 

The indirect causes which are equivalent to an absence of indi- 
viduals are (a) insufficient nutrition ; the effect of this is seen in the 
the fact that a well-fed cow served by a starved bull always produces 
males, and inversely. In other words, there is a close connection 
between nutrition and reproductive capacity. (@) Difference in age. 
Every individual at the time of its highest reproductive capacity tends 
to produce its own sex; and the preponderance of males is greatest 
when the male is considerably older than the female. This law was 
discovered by Hofacker and Sadler, and is supported by the 58,000 
cases reported on by Goehlert and Legoyt. 

We come, then, to this conclusion: Animals have by adaptation 
acquired the power, in the presence of abnormal sexual relations, of 
producing more individuals of the sex of which there is a want; and 
the same balance is maintained by the same methods when there are 


* Jenaisch. Zeitschr. f. Naturwiss., xvi. (1883) pp. 428-64. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 709 


‘at work indirect causes which are equivalent to a want of the indi- 
viduals of one sex. 

In another sense the influence of nutriment is of the greatest 
importance; notwithstanding the fact that a starving animal may 
reproduce itself numerously, the progeny are feebler than those of 
one which only produces as many as, under these conditions, can live 
and thrive. Surplus nutriment leads to the production of a stronger, 
and insufficient food to that of a weaker progeny. Domesticated. 
animals breed earlier, and are more fruitful than the wild ; townsmen 
and sedentary people more than countrymen who take much hard 
exercise. More children are conceived in summer than in winter ; 
and in Scotland, according to Haycraft, the maximum of conceptive 
capacity is simultaneous with that of the thermometer. Birds, bats, 
and insects breed less numerously than fishes, and especially than 
parasites who use up little or no force in movement. 

The differences we observe between males and females are easily 
explained when we consider the very different parts that they play in 
the physiology of reproduction; it must always be remembered 
that it is the office of the female to produce the material out of which 
the embryo is built up. 

The author concludes by reasserting his conviction that it is in 
the principle of natural selection that we must look for the explana- 
tion of the differences between the sexes. 


Rudimentary Placenta in Birds.*—One of the principal dis- 
tinctions between the Mammalia and the lower Vertebrata has been 
hitherto supposed to be the possession by the former of a placenta. 
M. Duval has, however, come to the conclusion that this structure is 
not exclusively confined to the Mammalia, but that it also exists, 
though in a rudimentary form, in birds. 

The allantois in passing inwards into the pleuro-peritoneal cavity 
does not become attached to the amnion or to the umbilical vesicle, 
but joins the chorion, becoming fused with it; it ends by forming 
a sac which incloses a mass of albumen; into this sac the villi of 
the chorion project, and an organ is thus formed which is completely 
analogous to the placenta of the Mammalia; the different form of 
the organ in birds and in mammals is evidently owing to the dif- 
ference between the oviparous and viviparous method of reproduction ; 
the villi of the chorion in Mammalia are attached to the body of the 
mother, while in birds the necessities of the case demand that they 
should be developed upon the opposite side of the chorion and attach 
themselves to the nutritive albumen. It is, however, quite intelli- 
gible that in an ovoviviparous vertebrate, where the egg has a thin 
membranous shell, the placentoid organ should become attached 
to the internal surface of the oviduct. This placenta of birds is 
therefore a rudimentary organ which enables us to understand how 
the placenta of the Mammalia may have originated. A physiological 
difference between the placenta of birds and of Mammalia is that in 


* Journ, Anat. et Physiol., xx. (1884) pp. 193-201 (4 pls.). See also this 
Journal, ante, p. 360. 


710 SUMMARY OF CURRENT RESEARCHES RELATING TO 


the former the exchange of gases takes place, of course, by the outer 
surface, so that the two functions of respiration and nutrition are 
relegated to two different portions of the placenta, while in mammals 
they both take place on the outer surface of the organ. 


Permanence of larval conditions in Amphibia.*—As a general 
rule the Amphibia when mature cease to breathe by means of gills; the 
latter disappear and respiration is carried on solely by means of the 
lungs. There are, however, a number of cases known, and they are 
increasing daily, where branchial respiration is carried on for a 
longer or shorter period of the life of the adult. LL. Camerano has 
lately paid some attention to this subject, and has investigated a 
certain number of these Amphibians, paying special attention to the 
dimensions of the adult animal, its organs of reproduction, colour, 
alimentary system, lungs, and nervous system. The period during 
which branchial respiration continues varies in different Am- 
phibia; the shortest known to him is in Salamandra aitra, the 
longest in Proteus anguineus, the axolotl, and Triton. In almost all 
the Amphibia of Europe cases are known of an abnormally short or 
abnormally long “ branchiate-period.” These may be divided into 
two classes: (1) those instances of simple hibernation, where the 
animal has not had time in a single summer to attain maturity ; and 
(2) other cases where the branchie remain functional for several years. 
In this respect, however, the Urodela differ from the Anura; the 
former are influenced by local conditions, such as food, presence of 
floods, &c., which render it necessary for them to continue an aquatic 
life though the development of the other organs of the body goes on 
quite as rapidly as in individuals that have adopted a terrestrial life. 
In the Anura, on the other hand, the permanence of the branchie for 
several years is accompanied by an incomplete development of other 
structures. Such cases are, however, rare, and are not, as in the 
Urodela, a modification owing to local causes, but are a reversion to 
an ancestral condition. 

The Amphibia as a class are clearly most nearly related to the 
fish, and the occasional permanence of a branchiate condition is the 
best proof of this relationship; it is, however, none the less possible 
that branchie were acquired later, and that the Amphibia were primi- 
tively land-dwellers, assuming the branchiate condition as a“ retrograde 
metamorphosis” by the adoption of an aquatic life. Keeping in view 
this possibility it is easy to understand how by artificial interference 
with the biological conditions, the Amphibia may pass from a 
branchiate to a pulmonate respiration and back again. 

The old division of Perennibranchiata and Caducibranchiata is 
therefore unphilosophical: the real proof of the adult condition of an 
Amphibian is the maturity of the reproductive organs, and its branchi- 
ate or pulmonate condition must be neglected since it is merely an 
instance of dimorphism dependent upon the influence of the environ- 
ment. 


* Mem. R. Accad. Sci. Torino, xxxy. (1883) 64 pp. (2 pls.). Natuiforscher, 
Xvil. (1884) pp. 273-4. 


ZOOLOGY AND BOTANY, MICROSOOPY, ETC. 7p a 


Embryo Fishes.*—The Bulletin of the United States Fish Com- 
mission contains a series of articles upon various matters connected 
with the development of fishes, embodying the results of the investiga- 
tions of Mr. J. A. Ryder during the year 1882. 

The mode of absorption of the yolk of the embryo shad differs in 
the absence of a vitelline circulation from that which obtains in 
Tylosurus (Belone), Fundulus, Esox, and Salmo. The great mass of the 
yolk in the shad embryo consists of coarse irregular masses of very 
clear protoplasmic matter, separated by a protoplasm which is opti- 
cally different. The covering of the yolk is a palish amber-coloured 
layer, quite different from the clear body of the yolk, and usually 
thicker at the end next the heart. The intestine lies in a longitudinal 
furrow on the dorsal aspect of the yolk-sac, and is never connected 
with it in this species. The yolk-sac is surrounded by a space 
filled with serous fluid. This space is capacious anteriorly, between 
the heart and the yolk, and this part is identified by the author 
with the segmentation-cavity. The delicate pericardial membrane 
that separates this cavity from the pericardial space may, possibly, be 
perforated. In Tylosurus the two cavities are certainly connected. 
The heart opens freely into the segmentation-cavity, and the appear- 
ance presented is that its persistent pulsation breaks up the yolk- 
substance into small spherules, sucks them out of the segmentation- 
cavity, and carries them into the body of the embryo. The corpuscles 
develope on the surface of the outer yolk-layer, and after a while drop 
into the serous fluid, appearing likethe white blood-cells of human blood. 
As development proceeds, the yolk-sac becomes pointed in front, and 
the external layer becomes thicker, while the pericardial membrane 
becomes funnel-shaped to fit the anterior part of the yolk-mass. Before 
the final disappearance of the yolk, the liver of the young fish becomes 
more developed, and the portal vein makes its way over the dorsal 
aspect of the yolk towards the venous end of the heart. As the 
peculiar amber-layer around the yolk persists to the last, it is probable 
that the central clear portion is transformed gradually into it. 

This is the history of the yolk-mass after the embryo is hatched, 
but as it grew in size before hatching, yolk-absorption must have 
taken place before the heart was sufficiently developed to be an active 
agent in the process. This must be by intussusception, and in the 
amber yolk-covering it is undoubted that a process of cell and blood- 
cell differentiation takes place. Mr. Ryder concludes that the hypo- 
blast of Gensch, said by that investigator to be the source from which 
the blood is derived, is the equivalent of the amber yolk-covering of 
the shad, and not the true hypoblast. This amber layer is a tempo- 
rary structure, which disappears entirely, and does not enter into the 
formation of any organ or membrane. The serous cavity around the 
yolk in the shad represents the body-cavity, and the outer covering 
of this, though only 1/2000 of an inch in thickness, contains epiblast, 
mesoblast, and hypoblast. 


* Bull. U.S. Fish Commission—Observations on the Absorption of the Yolk, 
the Food, Feeding and Development of Embryo Fishes, &c., pp. 179-205. Amer. 
Natural., xviii. (1884) pp. 395-8. 


(1 SUMMARY OF OURRENT RESEARCHES RELATING TO 


There is practically little difference between the modes of yolk- 
absorption in the chick and in the fish. 

The author brings forward facts to prove that there is between 
ova, even of allied genera, considerable differences, and that at no 
stage is there a positive identity. 

The mechanical construction, as it may be termed, of ova affects 
the course of their development. The Teleost ovum has a relatively 
enormous yolk, which must be included by the blastoderm in order 
to be absorbed, and this relatively large yolk has much to do with 
the difference observed between its development and that of a Mar- 
sipobranch or Amphibian. The eggs of the Salmonide have an 
abundance of oil-drops in the vitellus, especially just under the 
germinal disk. These by their buoyancy keep the disk constantly 
directed upward. The cusk, the crab-eater, Spanish mackerel, and 
moon-fish have eggs which are buoyant from the possession of a 
single large oil-sphere situated almost exactly opposite to the germinal 
disk, and thus keeping it face downwards—just the reverse of what 
occurs in the Salmonoids. Even after hatching, the young are at first 
unable to right themselves on account of the presence of the oil-drop. 
The cod ovum has no oil-drop, yet floats with the germinal disk 
downwards. That of Morone Americana (white perch) is adhesive 
and fixed with a very large oil-sphere, which keeps the disk on the 
lower side of the vitelline globe. The shad egg is non-adhesive, and 
heavier than water, and the germinal disk has a constant tendency to 
arrange itself at the side of the vitellus as viewed from above, though 
there is no oil to influence it. In Fundulus and Syngnathus the oil- 
drops appear uniformly distributed. The number of proto-vertebre or 
primary somites differs so much that while Tylosuwrus has so many as 
seventy-five pairs, Alosa has only eighteen to twenty. ‘The author 
ventures this bold remark: ‘‘ When our knowledge is more complete, 
we shall perhaps be able to distinguish the species apart by the eggs 
alone, just as botanists have used the characters presented by seeds to 
distinguish plants.” 


Development of Viviparous Minnows.*—J. A. Ryder describes 
the development of viviparous minnows, and particularly Gambrusia 
patruclis B. and G. 'The young fish develope within the body of the 
female parent, and within the follicles in which the eggs themselves 
are developed. The follicles, which are covered with a rich network 
of fine capillary vessels, assume the office of a respiratory apparatus, 
by which the gases are interchanged between the embryo and the 
parent fish. This follicle also acts as an egg-membrane, being 
actually perforated by a round opening (“follicular pore”) which is 
analogous to the micropyle of the ordinary fish-egg. The arrange- 
ment of the follicles of the ovary within the body of the female is 
described, and the peculiar differences between the two sexes in the 
arrangement of the viscera pointed out. The fibrous bands, which 
act as supports or stays to the basal portion of the anal fin of the 
male, which is modified as an intromittent organ, are also described. 


* Science, iii. (1884) p. 769. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 713 


The great difference in the sizes of the sexes is also referred to, the 
female weighing over six times as much as the male. 


Formation of and Reactions of Nuclei.*—C. Frommann finds 
that the application of acids to nuclei of non-amceboid cells does not 
result at first in a great change in the yellowish granules of the 
protoplasm, but that, after the acids have acted for some time, they 
become pale and can no longer be accurately distinguished from one 
another, and the nucleus appears to be surrounded by a distinct 
membrane. With amceboid cells the action of acids results in the 
appearance of a firm stroma and a firm more complete investing 
membrane; from the material of the protoplasmic granules new 
nuclei as well as separate longer filamentar structures are formed, 
or granules only are formed, and the protoplasm becomes clearer and 
more homogeneous. It must be borne in mind that we have here to 
do with artificial products. The author criticizes the views of Robin, 
and points out that structures, which we are bound to compare with 
nuclei, are to be found in the living colourless blood-corpuscles ; this 
has been proved by Stricker for non-defibrinated, and by Frommann 
for defibrinated blood, and Flemming speaks very positively as to the 
presence of nuclei in living leucocytes, whether in or out of the 
vessels of the larve of the salamander. 

If a homogeneous body, either spontaneously or after the action 
of chemical or physical reagents, differentiates into a formed and a 
homogeneous substance, the phenomenon may be explained by the 
supposition that both bodies were present, but had the same re- 
fractive index, or by supposing that the apparently homogeneous 
body was really so, and that the appearance of formed elementsis due 
to a differentiation of its substance into elements which are more 
highly refractive, and a clear substance which fills up the interspaces. 
The author is inclined to accept the latter view as applying to what 
obtains with nuclei, and supports it by various considerations. Ex- 
periments with salt solutions show that, after the fusion of the whole 
mass of the grains and granules with the nucleus, the whole structure 
thus formed becomes converted into a nucleus with sharply defined 
stroma and firm investment, so soon as spring or distilled water is 
added to the preparation. Various other experiments are detailed, 
the study of which is a matter of great importance for those who are 
making observations or experiments in connection with the phenomena 
exhibited by nuclei. 


Indirect Nuclear Division.t—E. Strasburger commences an essay 
on the subject of the controversy with regard to indirect nuclear 
division by an account of some specimens of the embryonic sac of 
Fritillaria imperialis, which had been prepared by Herr Heuser. He 
concludes from his numerous observations that it is very probable 
that in all typical processes of the indirect division of the cell-nuclei 
of plants there is a stage in which the segments of the nuclear 
filament divide longitudinally. This process is not, however, always 


* SB. Jenaisch, Gesell. f. Med. u. Naturwiss., 1883 (1884) pp. 4-16, 
+ Arch. f. Mikr. Anat., xxiii. (1884) pp. 246-304 (2 pls.). 


Ser. 2.—Vo.. IV. 3B 


714 SUMMARY OF CURRENT RESEARCHES RELATING TO 


found to be associated with the same definite arrangement of the 
segments in the nucleus, and it may either precede or succeed the 
arrangement of the segments into the nuclear plate. 

If we compare what is now known as regards plants with the 
results of studies on the division of the nuclei of animals we find 
that, with one exception, there is really no important difference 
between them. The investigation of plants shows that the spindle- 
shaped fibres almost certainly arise from compressed cytoplasm. The 
whole framework of the nucleus is to be found in the filamentar coils, 
while the nuclear cavity is only filled by homogeneous nuclear fluid. 
The whole mass of spindle-shaped fibres have their origin in the 
cytoplasm. 

The difference in the way in which cell-division is completed is a 
point of distinction between animals and plants, but it does not obtain 
in the lowest forms of either kingdom. The formation of the con- 
nective filaments in the separation of the cell-body is a distinctive 
characteristic of plants; but, notwithstanding this, the result of cell- 
division is the same in both plants and animals. 

In both we find that in the “ prophases” of nuclear division cyto- 
plasm is collected at the future poles of the cell-nucleus; this 
phenomenon is often very striking in animal-cells, and is especially 
well marked in ova. The nucleus becomes provided with two 
radiating systems, even before any dicentric arrangement can be 
detected in the cell-nucleus. The observations which the author has 
made lead him to think that the spindle-shaped fibres derived from 
the cytoplasm have a directive influence on nuclear division ; the 
frequently simultaneous division of nuclei in multinucleated cells may 
be easily supposed to be due to this influence and the surrounding 
cell-plasma. 

Strasburger thinks that some of the aberrant forms of division 
noted by Flemming may be explained by what he has seen in plants. 
The tub-shaped figures which become apparent during the arrange- 
ment of the segments in the testicular epithelium of the salamander 
call to mind what was seen in the embryo-sac of Fritillaria, and 
suggests that an explanation is to be found in the divarication of the 
daughter-segments on one side, and their approximation to one another 
on the other. In the red blood-cells of Salamandra the cell-nucleus 
becomes considerably enlarged during the development of the fila- 
mentar coil, and a large amount of cell-substance is taken up into the 
nuclear figure. If the spindle-shaped fibres form only a small figure 
in the cell, it would be clear that all the cytoplasm was not used up 
in forming this figure, and we should have a case similar to that seen 
in the pollen-mother-cells of Fritillaria persica, where in the first act 
of division granular cytoplasm is found between the spindle-shaped 
fibres. 

The ideas now derived from a study of animals and plants cannot be 
directly applied to the Protista, where the separate parts of the cell- 
body often undergo great changes and become adapted to new functions; 
we must greatly increase the number of our observations before we 
can hope to arrive at generalizations of universal value. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 715 


The function of the complicated nuclear division appears to be 
that of dividing the nucleus into two completely equal halves; in the 
first segmentation the parts are often very unequal in size, and if, 
as Heuser supposes, there are several different substances in the disks 
of the microsomes longitudinal division would be the safest means 
for distributing the substances equally to the two daughter-nuclei. 
It is quite clear that the nucleus has a nutrient function for the cell, 
though we do not yet know what its character is. In the internodes 
of the Characez we see the nucleus increasing in proportion to the 
mass of the increasing cytoplasm, although here cell-division does not 
accompany nuclear division; here indeed direct division of the 
nucleus (by constriction) takes the place of indirect division. 


Nucleus of the Auditory Epithelium of Batrachians.*—The 
results of J. Chatin have a double interest, as affording us more 
complete information as to several points in the comparative histology 
of the auditory epithelium, and as bearing on the structure of the 
nucleus. 

The study of the epithelial layer which invests the labyrinths of 
Batrachians demonstrates a close relationship between the sustaining 
and sensitive elements; they are intimately connected, and they 
undergo the same kind of modifications. What is true of Batrachians 
is true also of other vertebrates ; in the Mammalia, for example, there 
are auditory rods and ciliated cells, but between the two all inter- 
mediate stages are to be made out, and this even at some single 

int. 

As to the intranuclear corpuscles the author finds that, so soon as 
they have acquired their definite characters and become grouped in a 
plexus they are all perfectly identical; there is no trace of any 
nucleolus. In insects, Chatin has noted the inconstant character of 
the nucleoli, and Klein, working at certain glandular elements of the 
Batrachia, likewise bears witness to their absence. 


Epidermis of the Chick.t—C. Frommann has examined the 
epidermis of the chick during the last week of its stay in the shell, 
and finds in it granular cells and net-cells; the former are rounded 
or oval and contain granules which are fused into cords of various 
forms; these are connected with one another by filaments of various 
degrees of fineness, which traverse the delicate spaces left between 
them ; here and there, however, there are larger spaces. In neither 
case have the spaces any special wall. The body of the net-cell is 
traversed in all directions by a wide-meshed network ; part contains 
neither nuclei nor any aggregations of cell-substance, while in other 
parts the nodal points have nuclei. On the whole, the characters of 
the cells of the epidermis are the same as after the period when the 
chick leaves the egg. Certain differences are presented in the parts 
of the skin which are feathered, for there is there ordinarily a layer 
of small granules imbedded in a pale, finely granular substance, in 
which nuclei are either completely absent or are irregularly scattered 


* Ann. Sci. Nat. (Zool.), xvi. (1884) 5 pp. 
+ Jenaisch. Zeitschr. f. Naturwiss., xvii. (1884) pp. 941-50. 


3 BQ 


716 SUMMARY OF CURRENT RESEARCHES RELATING TO 


about ; such nuclei are always small and vary in character. Schenk 
has already noted the presence of non-nucleated cells in the ectoderm 
when describing the process of fusion of the folds of the amnion. 


Scales, Feathers, and Hairs.*—The idea largely taught to 
students that scales, feathers, and hairs are identical in nature is 
combatted by J. H. Jeffries. He considers the epiderm to be the 
primitive skin, if not the true one, as it is formed long before the 
corium, which is a late and very variable product of the mesoblast ; 
and because all the organs of sense are formed from it. The epiderm 
may be regarded as primitively consisting of a smooth mucous layer, 
an epitrichial layer, and perhaps an intermediate layer of parenchy- 
matous cells. In birds and mammals the outer layer is lost, and 
never renewed, while the middle layer becomes thickened and subject 
to various modifications, as drying, conversion into horn, &c., and 
enters into the structure of all the appendages. Scales are moulted 
and renewed, scuta are not. The toe-pads of birds may be seen to 
pass over into scuta on the sides of the toes of many birds. Scuta 
bear feathers as epidermal appendages—scales never do, thus pointing 
to scuta, which have a mucous layer and outer horn coat with a 
mesodermal core, as simple folds of the skin, not as appendages. 

The early stages of a feather and of a hair differ. The latter is 
formed in a solid ingrowth of the epiderm, the latter from the 
epiderm of a large papilla. A hair does not contain any of the 
mucous cells, while a considerable portion of a feather consists of 
them. The supposed homology between feathers and scales seems to 
fail before the facts that the mucous layer is absent in the latter, and 
that Studer has shown that the imagined scale-like nature of the 
remiges of penguins is a fallacy. Mr. Jeffries avows his belief in the 
distinct origin of the dermal appendages of the higher vertebrates, 
and asserts that the nakedness of the Amphibia is a strong argument 
against the identity of any of the avian appendages with those of 
reptiles and mammals. 


Locomotion of Animals over smooth Vertical Surfaces.j—Dr. 
H. Dewitz has extended his observations on this subject, at first 
confined to insects,t to a variety of other forms, including some 
Vertebrata. He finds that the same means, the exudation of a secre- 
tion, are adopted in many cases, even where sucking-disks are used. 
Thus the leech can walk on a wire network, on which the disks could 
not act by exhaustion of the air, and the secretion of the disks of 
Piscicola has been examined by Leydig. A long series of animals is 
enumerated from Worms and Hchinoderms to Apes among the 
Mammalia, which are known with more or less certainty to use similar 
means for climbing. 

The tree-frog (Hyla) maintains its hold as firmly within the 
exhausted receiver of an air-pump as in the open air, and in fact a 
piece of glass passed over the balls of the tips of the toes shows clear 


* Proc. Bost. Soc. Nat. Hist. Cf. Amer. Natural., xviii. 1884) p. 640. 

+ Pfliiger’s Arch. gesammt. Physiol., xxxiii. (1884) pp. 440-81 (3 pls.), See 
also infra, Insecta. 

t See this Journal, iii, (1883) p. 363. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 717 


traces of the secretion. If studied by sections, the ball of the foot 
exhibits on the upper surface some globular mucous glands imbedded 
in the cutis, and some elongated glands, imbedded in the connective 
tissue, on the lower side; this is the case on the balls of all the 
phalanges. In Rana temporaria, too, these dermal glands have a 
similar form, only being less numerous and long; they probably serve 
a similar function. 

The glands in Hyla are tubular, there is a tunica propria, and the 
cells are longish and somewhat cubical in longitudinal, but mostly 
hexagonal in transverse section; the nucleus, which is the only part 
which is stained readily by picrocarmine, lies at the lower end; the 
cells end distally in two pointed processes. The glands do not open 
in the annular furrow, but over the whole of the sole, especially at the 
hinder part; the ducts are lined by a cuticle which is shed with the 
skin. The spongy connective tissue of the ball of the toe is filled 
with lymph, and is thus rendered elastic, so that it adapts itself to 
inequalities of surface; balls of similar structure are found on the 
tarsal joints of Orthoptera. By fastening insects feet upper- 
most on the under side of a covering-glass which projects from a 
glass slide, the hairs which clothe the grasping lobes of the foot may 
be seen (e. g. in Musca erythrocephala) to be tipped with drops of trans- 
parent liquid. On the leg being drawn back from the glass, a 
transparent thread is drawn out, and drops are found to be left on the 
glass. 

The grasping apparatus is constructed as follows : The short grasp- 
ing foot-hairs in Telephorus and other Coleoptera are each traversed 
by a canal which opens at its extremity. Sundry long hairs on the 
lower side of the tarsal joints in Telephorus are connected with nervous 
filaments which lead from small ganglia, and thus constitute tactile 
organs. The observation of what appear to be nerve-fibres in the 
glands which supply the hairs with the sticky secretions is not suffi- 
ciently certain. 

In the Orthoptera the arrangement is different: thus the tarsus of 
a Locustid has the chitinous covering of the lower side rendered 
very flexible by being composed of small parallel tubes, the under- 
lying matrix is deeply plicate, and constitutes a large gland, whose 
secretion is transmitted through the chitinous tubes and through another 
intermediate chitinous layer to the surface. In the house-fly, the 
grasping foot-lobes appear to be only called into play when the insect 
has to walk on vertical smooth surfaces, for in other cases they hang 
loosely down. So also the Echinoidea use the tube-fect only on 
vertical surfaces. 

The use of a glutinous secretion for walking has been shown by 
Burmeister for Dipterous larve; Dr. Dewitz finds the larva of a 
Musca to use for the purpose a liquid ejected from the mouth. Thus, 
too, the larve of Leucopis puncticornis accomplish their loop-like 
walk—the liquid in this case comes from both mouth and anus. A 
Cecidomyia-larva is able to leap by fixing its anterior end by means 
of a liquid of this kind, The larva of the alder-leaf beetle (Galeruca) 
moves by drawing up its hinder end, fixing it thus, and carrying the 


718 SUMMARY OF CURRENT RESEARCHES RELATING TO 


anterior part of the body forward with its feet until fully extended, 
when it breaks the glutinous adhesion; under even the lower powers 
of the Microscope the drops of secretion may be seen on the feet. 
A Chrysopa-larva (probably Hemerobius) was able to crawl well on 
vertical glass, but on sand the feet became clogged ; some larve of this 
group, on the other hand, had the grasping lobes but slightly 
developed, and these adopted the loop mode of walking; the 
adhesion of the posterior end of the body was so strong that many 
larve long resisted all attempts to shake them off by twisting the 
glass suddenly round. 

Among the Hymenoptera the ventral feet of some sawflies have 
this power. Most spiders are devoid of it, but leaping spiders leap 
and crawl on vertical surfaces, and have grasping disks for adhesion. 
Among Celenterata, Hydra may be seen to excrete mucous adhesive 
matter from its foot. 


Zoology of the Voyage of the ‘ Alert.’*—The Zoological collec- 
tions made by Dr. R. W. Coppinger, Staff-Surgeon H.M.S. ‘ Alert’ 
in the Melanesian Seas and in the Western Indian Ocean were so 
large that the Trustees of the British Museum ordered the account 
of them to be published as a separate volume. The magnitude of 
the collection may be inferred from the statement that “irrespective 
of a number of specimens set aside as duplicates not less than 3700 
referable to 1300 species were incorporated in the National Collec- 
tion ;” of these the most important were marine invertebrates, and 
490 of the species are either new or are additions to the Museum. 
The specimens were admirably preserved, and collected, Dr. Giinther 
says, with singular judgment. 

In place of the one species of lancelet which Dr. Ginther thought 
to be cosmopolitan, six distinct species are, he now thinks, to be 
recognized. 

The Mollusca are treated of by Mr. Edgar A. Smith, who finds that 
of the Melanesian specimens the general character is Malayan. 

The Echinodermata are dealt with by Prof. F. Jeffrey Bell, who 
found that 30 of the 124 Melanesian species were new; fifteen of 
these were Comatulids. He adduces evidence to show that pattern 
of coloration is not as important a characteristic of the species of 
Ophiothriz as has been generally supposed. He proposes some altera- 
tions in the mode of formulating the characters of Crinoids. Having 
had the opportunity of examining a large collection from the Sydney 
Museum he finds that no view can be more erronecus than one which 
speaks of an Australian (marine) fauna without some sort of qualifica- 
tion; Cape York and Port Molle are as much part of Australia 
as Port Jackson, but between the two faune the resemblance is as 
slight as is in the nature of things possible. He concludes, in fact, 
that “to-day, as in those Tertiary times when a wider sea separated 
the Australian from the Asiatic continent, there are forms whose 
breadth of range is coincident rather with isothermal lines than with 
topographical boundaries.” The marked manner in which the species 


* “Report on the Zoological Collections made in the Indo-Pacific Ocean during 
the voyage of H.M.S. Alert, 1881-2.’ 8yvo, London, 1884, 684 pp. (54 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 719 


of Crinoids vary among themselves leads to the hope that the details 
of the tropical fauna may be elucidated by their aid. 

Similarly, according to Mr. Miers, the Crustacea collected have 
one-third of their species widely distributed through the Indo-Pacific 
region ; the affinity of the Australian with the European Amphipoda 
is very remarkable, some of the species being identical. Mr. Miers 
gives a very elaborate table of the distribution of the higher 
Crustacea on the East Coast of Africa and the adjacent islands. 

Mr. 8. O. Ridley deals with the Alcyonaria and Spongiide; of 
the former there are 38 Melanesian species, and the author thinks 
that few novelties are in the future to be expected from the shallow 
water; one-third of the Alcyonaria are new to science; Psilacabaria 
is a new genus of Melitheids, and its species is remarkable for the 
large size of its spicules. Thirty-eight per cent. of the Melanesian 
sponges are certainly new to science; the greater number of novelties 
belong to the Ceratosa; as to individual variation, it is noted that 
this often affects the size of the spicules; variation in form of the 
spicules is less common, that of external form is sometimes very 
striking. Only a quarter of the species of sponges are known to 
occur outside the Australian seas; the most widely ranging are the 
most generalized, but in some cases it is possible that the same specific 
characters have been independently acquired. Twenty-eight per cent. 
of the sponges obtained in the Western Indian Ocean were found to 
be identical with those of the Australian Seas. The most striking 
point with regard to the sponges appears to be “the comparative 
scarcity of forms showing marked distinctive characters of generic 
importance which are not also found in the more familiar Atlantic 
fauna.” 


B. INVERTEBRATA. 


Origin of Fresh-water Faune.*—Prof. W. J. Sollas points out 
that the poverty of fresh-water faunz, as compared with marine, is 
commonly attributed to a supposed inadaptability on the part of 
marine organisms to existence in fresh water. That this is erroneous 
is shown by the existence of fresh-water jelly-fish such as Limnocodium, 
and still more directly by the experiments of Beudant, who succeeded 
in accustoming several kinds of marine mollusca to a fresh-water 
habitat. The view of Von Martens that the severity of a fresh-water 
climate is prohibitive of the existence of most marine forms in rivers 
is insufficient, and a more thorough-going explanation is necessary. 
This is to be found in a study of the means by which the distribution 
of marine animals is secured. 

In the case of stationary forms, free-swimming embryos are distri- 
buted over wide areas by currents, and they can never pass from the sea 
into rivers, in which the current is always directed seawards. Nor, 
probably, could an attached form once introduced into a river perma- 
nently establish itself so long as its propagation took place exclusively 
through free-swimming larve, for these would be gradually borne 


* Nature, xxx. (1884) p. 163. 


720 SUMMARY OF CURRENT RESEARCHES RELATING TO 


out to sea. Hence, fresh-water animals should not, as a rule, pass 
through a free larval stage of existence, nor, as a matter of fact, do 
they. In Hydra, fresh-water sponges, and Polyzoa, the young usually 
emerge from a horny cyst in the complete state. In the Unionide, 
the glochidium-stage provides for distribution without involving a 
seaward journey. The young of fresh-water molluscs do not enter 
upon a free existence till they are similar to their parents, and 
Paludina is viviparous. The suppression of a free-swimming larval 
stage not only occurs in fresh-water, but in many marine invertebrates. 

This is connected with the fact that the larval stage is in a position 
of disadvantage as compared with the adult. Hence there is an 
advantage to the organism if the larval stage can be passed over in a 
state of seclusion. From this various other modifications follow ; 
development in seclusion involves a supply of accessible food, hence 
the appearance of yolk and other kinds of nourishment furnished by 
the parent to the imprisoned embryo. Again, the secluded larva 
being spared the drudgery of working for its own existence, and 
supplied with nutriment in a form that puts the least tax on its 
digestive powers, a larger balance of energy remains available for 
metamorphic changes. Thus arise the phenomena of accelerated and 
abbreviated development. Further, the shortening of the larval life 
probably leads to the lengthening of the adult life, and shifts the 
chances of variation and selection forward into the adult stage. Thus, 
animals which hatch out in a complete state will most probably suffer 
modifications of that, and not of previous ones, except very indirectly. 
Here we discover a direct tendency towards a mode of development 
which explains the “arborescent” character of our zoological ciassifi- 
cations, i.e. the tendency of the tree of life is now to produce leaves 
rather than new branches. In the case of fresh-water faune very 
direct reasons have existed for the suppression of the free larval 
stage. In this connection may be noticed the richness in species and 
the poverty in genera of the fresh-water mollusca. 

In discussing the origin of fresh-water faune there are three 
hypotheses from which we have to select: (1) that marine forms have 
migrated into rivers; (2) that they have migrated into marshes, and 
thence into rivers; and (3) that marine areas have been converted 
into fresh-water ones. The last course has been the most usual, 
especially in the case of non-locomotive forms. Hence the origin of 
fresh-water invertebrates is connected with the great movements 
which have affected the earth’s crust. 


Pelagic Fauna of Fresh-water Lakes.*—O. E. Imhoff first deals 
with the “ Langensee,” and refers to the remarks of Crisp as to the 
synonymy of some of his species with those previously described by 
Gosse, pointing out certain errors or lacune in Gosse’s descriptions. 
Dealing with the pelagic fauna of four of the lakes of northern Italy 
he adds to them one Flagellate, Dinobryon divergens Imhoff, a species — 
of Ceratium, Conochilus volvox, Anurceea cochlearis and longispina, 
Asplanchna helvetica, and a species of Polyarthra. Among the 


* Zool, Anzeig., vii. (1884) pp. 321-7. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. EAL 


Cladocera we have Bythotrephes longimanus of Leydig and a species 
of Daphnia. 

The pelagic fauna of fresh-water lakes consists of genera which, 
like Piscicola or Argulus, are occasionally found there, and others 
which do not voluntarily leave it; the latter are divisible into such 
as live on true pelagic animals or plants, like Acineta, Vorticella, and 
ELpistylis, and others which are truly pelagic (Hupelagici Pavesi), such 
as the genera referred to above and Bosmina and Leptodora. 


Lowest and Smallest Forms of Life as revealed by the modern 
Microscope.*—The following are some of the principal passages of 
the lecture delivered by the Rev. Dr. W. H. Dallinger, at the 
Montreal meeting of the British Association. The ‘Times’ says ¢ 
of it, “But, perbaps, the most popular and most generally 
instructive feature in connection with biology at Montreal was the 
address of Dr. Dallinger, in which he exhibited by word and picture 
the wonderful revelations of the lowest forms of life made by the 
modern Microscope ; and in which he showed that however easy it 
may seem to be to generate life in the proper conditions, no one has 
ever yet succeeded in producing ‘ spontaneous generation.’ And here 
Dr. Dallinger is in accord with the most competent scientific 
opinion.” 

Dr. Dallinger said :—‘ The labour, enthusiasm, and perseverance 
of thirty years, stimulated by the insight of a rare and master mind, 
and aided by lenses of steadily advancing perfection, has enabled the 
student of life-forms not simply to become possessed of an incon- 
ceivably broader, deeper, and truer knowledge of the great world 
of visible life, of which he himself is a factor, but also to open 
up and penetrate into a world of minute living things so ulti- 
mately little that we cannot adequately conceive them, which are, 
nevertheless perfect in their adaptations and wonderful in their 
histories. These organisms, while they are the least, are also the 
lowliest in nature, and are totally devoid of what is known as organic 
structure, even when scrutinized with our most powerful and perfect 
lenses. Now, these organisms lie on the very verge and margin of 
the vast area of what we know as living. They possess the essential 
properties of life, but in their most initial state. And their number- 
less billions, springing every moment into existence wherever putre- 
scence appeared, led to the question, How do they originate ?—do 
they spring up de novo from the highest point on the area of not-life 
which they touch? Are they, in short, the direct product of some 
yet uncorrelated force in nature, changing the dead, the unorganized, 
the not-living into definite forms of life ? 

Now this is a profound question, and that it is a difficult one there 
can be no doubt. But that it is a question for our laboratories is 
certain. And after careful and prolonged experiment and research, 
the legitimate question to be asked is: Do we find that in our 
laboratories and in the obscured processes of nature now that the not- 
living can be, without the intervention of living things, changed into 
that which lives? To that question the vast majority of practical 

* ‘Times,’ 2nd September, 1884. + Ibid., 4th September, 1884, 


722 SUMMARY OF CURRENT RESEARCHES RELATING TO 


“biologists answer without hesitancy, ‘No, we have no facts to justify 
such a conclusion. Professor Huxley shall represent them. He 
says: ‘The properties of living matter distinguish it absolutely 
from all other kinds of things;’ and, he continues, ‘the present state 
of our knowledge furnishes us with no link between the living and 
the not-living.’ Now let us carefully remember that the great doc- 
trine of Charles Darwin has furnished biology with a magnificent 
generalization—one, indeed, which stands upon so broad a basis that 
great masses of detail and many needful interlocking facts are of 
necessity relegated to the quiet workers of the present and the earnest 
labourers of the years to come. But it is a doctrine which cannot be 
shaken. The constant and universal action of variation, the struggle 
for existence, and the ‘ survival of the fittest,’ few who are competent 
to grasp will have the temerity to doubt. And to many, that which 
lies within it as a doctrine and forms the fibre of its fabric, is the 
existence of a continuity, an unbroken stream of unity running from 
the base to the apex of the entire organic series. The plant and the 
animal, the lowliest organized and the most complex, the minutest 
and the largest, are related to each other so as to constitute one 
majestic organic whole. Now, to this splendid continuity practical . 
biology presents no adverse fact. All our most recent and most 
accurate knowledge confirms it. 

But the question is—Does this continuity terminate now in the 
living series, and is there then a break—a sharp, clear discontinuity, 
and beyond, another realm immeasurably less endowed, known as the 
realm of Not-life? Or, does what has been taken for the clear-cut 
boundary of the vital area, when more deeply searched, reveal the 
presence of a force at present unknown, which changes not-living into 
the living, and thus makes all nature an unbroken sequence and a 
continuous whole? That this is a great question, a question involy- 
ing large issues, will be seen by all who have familiarized themselves 
with the thought and fact of our times. But we must treat it purely 
asa question of science; it is not a question of how life first appeared 
upon the earth, it is only a question of whether there is any natural 
force now at work building not-living matter into living forms. Nor 
have we to determine whether or not, in the indefinite past, the not- 
vital elements on the earth, at some point of their highest activity, 
were endowed with or became possessed of the properties of life. On 
that subject there is no doubt. The elements that compose proto- 
plasm—the physical basis of all living things—are the familiar 
elements of the world without life. The mystery of life is not in the 
elements that compose the vital stuff. We know them all; we know 
their properties. The mystery consists solely in how these elements 
can be so combined as to acquire the transcendent properties of life. 
Moreover, to the investigator it is not a question of by what means 
matter dead—without the shimmer of a vital quality—became either 
slowly or suddenly possessed of the properties of life. Hnough 
for us to know that whatever the power that wrought the change, 
that power was competent, as the issue proves. But that which 
calm and patient research has to determine is, whether matter 


ZOOLOGY AND BOTANY, MICROSOOPY, ETC. (pea 


demonstrably not living can be, without the aid of organisms already 
living, endowed with the properties of life. 

Judged of hastily and apart from the facts, it may appear to some 
minds that an origin of life from not-life, by sheer physical law, 
would be a great philosophical gain, an indefinitely strong support 
of the doctrine of evolution. If this were so, and indeed so far as it 
is believed to be so, it would speak and does speak volumes in favour 
of the spirit of science pervading our age. For although the vast 
majority of biologists in Europe and America accept the doctrine of 
evolution, they are almost unanimous in their refusal to accept, as in 
any sense competent, the reputed evidence of ‘spontaneous genera- 
tion’ : which demonstrates at least, that what is sought by our leaders 
in science is not the mere support of hypotheses, cherished though 
they may be, but the truth, the uncoloured truth, from nature. But 
it must be remembered that the present existence of what has been 
called ‘spontaneous generation,’ the origin of life de novo to-day by 
physical law, is by no means required by the doctrine of evolution. 
Prof. Huxley, for example, says, ‘If all living beings have been 
evolved from pre-existing forms of life, it is enough that a single par- 
ticle of protoplasm should once have appeared upon the globe, as the 
result of no matter what agency; any further independent formation 
of protoplasm would be sheer waste. And why? we may ask. 
Because one of the most marvellous and unique properties of proto- 
plasm, and the living forms built out of it, is the power to multiply 
indefinitely and for ever ! 

What need, then, of spontaneous generation? A locomotive on 
a great journey, that is specifically endowed with the power to 
generate its own steam, surely does not need stationary engines placed 
all along the line to generate steam for it. It is certainly true that 
evidence has been adduced purporting to support, if not establish, 
the origin in dead matter of the least and lowest forms of life. But 
it evinces no prejudice to say that it is inefficient. For a moment 
study the facts. ‘The organisms which were used to test the point at 
issue were those known as septic. The vast majority of these are 
inexpressibly minute. The smallest of them, indeed, is so small that 
50 millions of them, if laid in order, would only fill the one-hun- 
dredth part of a cubic inch. Many are relatively larger, but all are 
supremely minute. Now, these organisms are universally present 
in enormous numbers, and ever rapidly increasing—in all moist 
putrefaction over the surface of the globe.” Referring to an experiment 
made with a few shreds of fish muscle and brain in pure water, and 
which in a brief space gave rise to a multitude of many living and 
moving organisms, Dr. Dallinger asked, “ How did these organisms 
arise? The water was pure; they were not discoverable in the 
fresh muscle of fish. Yet in a dozen hours the vessel of water is 
peopled with hosts of individual forms which no mathematics could 
number! How did they arise—from universally diffused eggs, or 
from the direct physical change of dead matter into living forms ? 

Twelve years ago the life-histories of these forms were unknown. 
We did not know biologically how they developed. And yet with 


724 SUMMARY OF CURRENT RESEARCHES RELATING TO 


this great deficiency it was considered by some that their mode 
of origin could be determined by heat experiments on the adult 
forms. Roughly the method was this. It was assumed that nothing 
vital could resist the boiling point of water. Fluids containing 
full-grown organisms in enormous multitudes, chiefly bacteria, were 
placed in flasks, and boiled for from 5 to 10 minutes. While they 
were boiling the necks of the flasks were hermetically closed, and the 
flask was allowed to remain unopened for various periods. The 
reasoning was: Boiling has killed all forms of vitality in the flask. 
By the hermetical sealing nothing living can gain subsequent access 
to the fluid; therefore, if living organisms do appear when the flask 
is opened, they must have arisen in the dead matter de novo by 
spontaneous generation. But if they do never so arise the probability 
is that they originate in spores or eggs. Now it must be observed 
concerning this method of inquiry that it could never be final ; it is 
incompetent by deficiency. Its results could never be exhaustive 
until the life-histories of the organisms involved were known. And 
further, although it is a legitimate method of research for partial 
results, and was of necessity employed, yet it requires precise and 
accurate manipulation. A thousand possible errors surround it. It 
can only yield scientific results in the hands of a master in physical 
experiment. And we find that when it has secured the requisite skill, 
as in the hands of Prof. Tyndall for example, the result has been 
the irresistible deduction that living things have never been seen to 
originate in not-living matter. Then the ground is cleared for the 
strictly biological inquiry, How do they originate ? 

To answer that question we must study the life-histories of the 
minutest forms with the same continuity and thoroughness with which 
we study the development of a crayfish or a butterfly. The difficulty 
in the way of this is the extreme minuteness of the organisms. 
We require powerful and perfect lenses for the work. Happily 
during the last fifteen years the improvement in the construction of the 
most powerful lenses has been great indeed. Prior to this time there 
were English lenses that amplified enormously. But an enlargement 
of the image of an object avails nothing if there be no concurrent 
disclosure of detail. Little is gained by expanding the image of an 
object from the ten-thousandth of an inch to an inch, if there be not 
an equivalent revelation of hidden details. It is in this revealing 
quality, which I shall call magnification as distinct from amplification, 
that our recent lenses so brilliantly excel. It is not easy to convey 
to those unfamiliar with objects of extreme minuteness a correct idea 
of what this power is. But at the risk of extreme simplicity, and to 
make the higher reaches of my subject intelligible to all, I would 
fain make this plain.” Dr. Dallinger then went on to give a series of 
greatly magnified illustrations, beginning with the sting of the bee, 
and going on through a long series of interesting specimens of the 
lowest forms of life. He described and illustrated with great 
minuteness experiments in the generation of these forms of life, 
from all of which he maintained it to be clearly proved that dead 
matter cannot be developed into living. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 725 


“ We conclude,” he said, “ with a definite issue—viz. by experiment 
it is established that living forms do not now arise in dead matter. 
And by study of the forms themselves it is proved that, like all the 
more complex forms above them, they arise in parental products. 
The law is as ever, only the living can give rise to the living.” 


Intelligence in the Lowest Animals.*—“ No one,” writes Dr. G. 
J. Romanes, “ can have watched the movements of certain Infusoria 
without feeling it difficult to believe that these little animals are not 
actuated by some amount of intelligence. Even if the manner in 
which they avoid collisions be attributed entirely to repulsions set up 
in the currents which by their movements they create, any such 
mechanical explanation certainly cannot apply to the small creatures 
seeking one another for the purposes of prey, reproduction, or as it 
sometimes seems, of mere sport. There is.a common and well-known 
rotifer whose body is of a cup shape provided with a very active tail, 
which is armed at its extremity with strong forceps. I have seen a 
small specimen of this rotifer seize a much larger one with its forceps 
and attach itself by this means to the side of the cup. The large 
rotifer at once became very active, and swinging about with its burden 
until it came to a piece of weed, it took firm hold of the weed with its 
own forceps, and began the most extraordinary series of movements, 
which were obviously directed towards ridding itself of its encum- 
brance. It dashed from side to side in all directions with a vigour 
and suddenness which were highly astonishing, so that it seemed as if 
the animalcule would either break its forceps or wrench its tail from 
its body. No movements could possibly be better suited to jerk off 
the offending object, for the energy with which the jerks were given, 
now in one direction and now in another, were, as I have said, most 
surprising. But not less surprising was the tenacity with which the 
smaller rotifer retained its hold. ... This trial of strength, which 
must have involved an immense expenditure of energy in proportion 
to the size of the animals, lasted for several minutes, till eventually 
the small rotifer was thrown violently away. It then returned to the 
conflict, but did not succeed a second time in establishing its hold. 
The entire scene was as like intelligent action on the part of both 
animals as could well be imagined, so that if we were to depend 
upon appearances alone, this one observation would be sufficient to 
induce me to attribute conscious determination to these microscopical 
organisms. 

But without denying that conscious determination may have been 
present, or involving ourselves in the impossible task of proving such 
a negative, we may properly affirm that until an animalcule shows 
itself to be teachable by individual experience we have no sufficient 
evidence derived or derivable from any number of such apparently 
intelligent movements that conscious determination is present. 
Therefore I need not wait to quote the observations of the sundry 
microscopists who detail facts more or less similar to the above, with 
expressions of their belief that microscopical organisms display a 


* ‘ Animal Intelligence,’ 8vo, London, 1882. 


726 SUMMARY OF CURRENT RESEARCHES RELATING TO 


certain degree of instinct or intelligence as distinguished from 
mechanical or wholly non-mental adjustment. But there are some ob- 
servations relating to the lowest of all animals, and made by a com- 


petent person which . .. in my opinion prove that the beginnings 
of instinct are to be found so low down in the scale as the Rhizo- 
poda.” 


The observations of Mr. H. J. Carter are then quoted.* One 
relates to Afthalium, which will make its way over the side of a watch- 
glass to get to the sawdust in which it has been living. In another 
case he saw an Amcba climb up the stalk of an Acineta which con- 
tained a young one (“tender and without poisonous tentacles”), place 
itself round the ovarian aperture, receive the young one, incept it, 
descend from the parent, and creep off with it. This Dr. Romanes 
considers, although certainly very suggestive of something more than 
mechanical response to stimulation, is not sufficiently so to justify us 
in ascribing to these lowest members of the zoological scale any rudi- 
ment of truly mental action. The subject, however, is here full of 
difficulty, and not the least so on account of the Amebe not only 
having no nervous system, but no observable organs of any kind, so 
that, although we may suppose that the adaptive movements described, 
by Mr. Carter were non-mental, it still remains wonderful that these 
movements should be exhibited by such apparently unorganized 
creatures, seeing that as to the remoteness of the end attained, no less 
than the complex refinement of the stimulus to which their adaptive 
response was due, the movements in question rival the most elaborate 
of non-mental adjustments elsewhere performed by the most highly 
organized of nervous systems. 

In Ceelenterates Dr. Romanes notices M‘Crady’s account of a 
medusa which carries its larve on the inner side of its bell, moving 
the manubrium from side to side to give suck to the larve on the 
sides, but he does not consider this is due to intelligence. The mode 
in which Sarsia seeks the light is in the nature of a reflex action, and 
he does not concur in Dr. Himer’s distinction between the “involun- 
tary ” and “ voluntary ” movements of medusze. 

Some of the natural movements of the Echinodermata, as also 
some under stimulation, are very suggestive of purpose, but Dr. 
Romanes has satisfied himself that there is no adequate evidence of 
the animals being able to profit by individual experience, so that there 
is no adequate evidence of their exhibiting truly natural phenomena. 

Of Vermes, the only instances cited are Mr. Darwin’s observations 
on earth-worms, and Sir E. Tennent’s on Ceylon land-leeches. 

In Mollusca, the more important observations relate to snails, 
limpets, and oysters. There is no doubt, he considers, that if a larger 
sphere of opportunity permitted, adequate observation of the Cepha- 
lopoda would prove them to be much the most intelligent members of 
the Sub-kingdom. 

The foregoing occupies pp. 18-30 of Dr. Romanes’s book ; the 
remainder (pp. 31-498) deals with Ants, Bees and Wasps, Spiders and 
Scorpions, remaining Articulata and the Vertebrates. 


* Ann. and Mag. Nat. Hist., xii. (1863) pp. 45-6. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 127 


Mollusca. 


New Type of Mollusc.*—W. H. Dall describes a remarkable new 
form of mollusc, being a pelecypod or lamellibranch with an internal 
shell. 

The animal is about 1 in. in length, somewhat of the shape of a 
small globose Cyprea, of inflated ovoid form, translucent, jelly-like, 
dotted above with small, rounded papille, which appear of an opaque 
white on the general translucent ground. The mantle which covers 
the dome of the body is tough and thick: the sides are smooth, and 
nearly free from papille. The superior median line is a little 
depressed. The basal part of the anterior end in life is prolonged 
beyond the general mass in a wide trough, with the convexity up- 
ward, and somewhat expanded at its anterior extremity. About one- 
third of the way from the anterior end, the mantle is perforated by 
an orifice, which pierces it in the vicinity of the mouth. The edges 
of this orifice project from the general surface, and it is lined with 
close-set, small papilla. At about the same distance from the 
posterior end is another tubular perforation, holding a similar rela- 
tion to the anus; which has, however, plain edges, and is not in- 
ternally papillose. 

Turning the animal over, we find the anterior trough of the 
mantle prolonged backward, like a slit with plain edges, to about the 
posterior third; from this projects a narrow, hatchet-shaped foot, 
with a strongly marked byssus-gland at its posterior angle; from this 
a bunch of white byssus extends to the stone or other object to which 
the mollusc attaches itself. The cavity of the mantle extends some 
distance behind the commissure of the pedal opening. The anterior 
point of the foot is roofed by the trough-like expansion above men- 
tioned. The mouth is provided with two pairs of small palpi. Two 
gills, very finely microscopically laminate, extend backward from 
near the mouth, on each side, to the posterior end of the body, the 
wider one being the inner: between their posterior ends a thin 
reticularly perforate veil connects the two pairs, and shuts off the 
anal area from the rest of the mantle cavity. The intestine contains 
a hyaline stylet, and is considerably convoluted ; but the viscera offer 
no marked peculiarities when compared with ordinary pelecypods. 
The shells are enclosed in two little sacs in the substance of the 
mantle. The umbones are near together, apparently connected by a 
brown gristle resembling an abortive ligament, and are nearly over 
the heart. The valves are about 10 mm. long and 1 mm. wide, 
destitute of epidermis, prismatic or pearly layers. There are no 
muscular or pallial impressions, no adductors, hinge, or teeth. The 
resemble in form the exterior of Gervillia, as figured by Woodward, 
and are pure white. As they lie in the body, they diverge at a rather 
wide angle from the beaks, forward. The embryonic valves are 
retained like two tiny bubbles on the umbones. 

Whatever be its relations to the higher groups, a point to be 
determined by further study, there can be no doubt that the animal 


* Science, iv. (1884) pp. 50-1. 


728 SUMMARY OF CURRENT RESEARCHES RELATING TO 


forms the type of a new family, Chlamydoconcha, and the author 
gives it the name of Chlamydoconcha Orcutti. It is evident already, 
that the genus does nothing toward bridging the gap between the gas- 
tropods and pelecypods, but is simply a remarkably aberrant form 
of the latter group, and probably derived from some form with an 
external shell. 

Taking-in of Water in relation to the Vascular System of 
Molluses.*—E. Ray Lankester, while recognizing that the supposi- 
tion that water is admitted by pores into the vascular system of 
molluses is supported by the commonly received doctrine that water 
is admitted by the madreporite to mix with the ccelomic fluid of 
Echinoderms, and that its correlated outpouring is favoured by the 
undoubted fact that the ccelomic fluid is occasionally shed through 
the dermal pores of the earthworm, doubts its occurrence in molluscs 
in consequence of having ascertained the presence of hemoglobin in 
the plasma of the blood-fluid of Planorbis, and in the corpuscles of 
Solen legumen. In Solen no shedding-out of blood-fluid occurs while 
the surface of the animal is uninjured, and the complete distension of 
the foot is produced by the simple mechanism of a rapid flow of 
blood from the mantle and body into the foot. Planorbis presents. 
evidence of essentially the same kind. 

A distinction must be made between the outpouring of the 
vascular fluid and the introduction of water through pores on the 
surface ; on the whole there seems to be no sufficient proof that the 
pericardium of molluscs is in any case (except that of the 
Neomeniz) a blood-space; and, therefore, the blood cannot escape 
through it and the renal organs to the exterior. 

The view that water is introduced by pores in the foot is not 
supported by Lankester’s observations on Anodon or Solen, and these 
pores must be demonstrated, by the supporters of the doctrine, in a 
way which will satisfy a histologist, and the evidence must not be 
allowed to rest on experiments made by the diffusion of a soluble 
colouring matter; it is to be noted that Griesbach, the present leading 
supporter of the doctrine, has found that finely divided coloured 
powder cannot be made to enter the vascular system through the 
surface of the foot. 


Eyes and other Sense-Organs in the Shells of Chitonide.t— 
H. N. Moseley, on examining a specimen of Schizochiton incisus 
dredged in the Sulu Sea, was “astonished to remark on the shells 
certain minute, highly refracting, rounded bodies arranged in rows 
symmetrically.” On further examination they were found to be eyes, 
and on search being made in other genera, they were detected in the 
majority, but in each genus they differ more or less in structure and 
arrangement. These eyes are entirely restricted to the outer surface 
of the shells on their exposed areas, and do not extend on to the 
lamine of insertion; they are mostly circular in outline, and measure 
from 1/175 to 1/600 in. They are surrounded and set off by a 
narrow zone of dark pigment, and in the centre of each convex spot 


* Zool. Anzeig., vii. (1884) pp. 343-6. 
+ Ann. and Mag. Nat, Hist., xii, (1884) pp. 141-7. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 729 


is a smaller darker area, due to the outline of the iris, but with a 
brilliant speck of totally reflected light, due to the lens. Numerous 
longitudinal canals lodge a specially large stem of soft tissue and 
nerves, which ramifies towards the surface and terminates either in 
eyes or in peculiar elongated bodies which are, apparently, organs of 
touch. From these latter the eyes may be supposed to have arisen by 
modification. The cornes, which are calcareous, are seen in section 
to be formed of a series of concentric lamelle ; the pear-shaped cavity 
of the eye is lined by a dark brown pigmented choroid of a stiff and 
apparently somewhat chitinous texture, The lens is perfectly trans- 
parent and strongly biconvex. At some distance from the eye the 
optic nerve is a compact strand, but in the very long tube continuous 
with the choroid its numerous fine fibres are much separated from one 
another. The retina is formed on the type of that of Helix; and not 
as might be supposed, on that of the dorsal eyes of Oncidium ; it is not 
perforated by the optic nerve, but it is composed of a single layer of 
very short, but extremely distinct and well-defined rods, with their 
ends directed towards the light. A number of the fibres of the nerve 
do not enter the retina at all, but terminate in small plugs of tissue 
corresponding to the minor organs of touch; they appear to form a 
sensitive zone round each eye. The choroid sacs have a curious open 
fold which calls to mind the choroid fissure. In some genera—e. g. 
Chiton—eyes are entirely absent, though the small and large touch- 
organs are present. 

The difficult problem of the classification of the Chitonide will 
probably be rendered easier, owing to the differences in arrangement 
and number of the eyes in different genera; in Corephium aculeatum 
there must be 3000 on the anterior shell alone, counting only those 
in good condition; and on the remaining shells as many as 8500. 

Prof. Moseley has been unable to trace the nerves to their source, 
but he doubts not that they proceed from the parietal (branchial) 
nerve. He concludes that the tegmentary part of the shell of the 
Chitonide is something swi generis, entirely unrepresented in other 
Mollusea. Its chief function seems “to be to act asa secure protection 
to a most extensive and complicated sensory apparatus, which in the 
Chitonide takes the place of the ordinary organs of vision and touch 
present in other Odontophora,” There are some curious resemblances 
to the Brachiopoda, 

The eyes are ordinarily hard to see on a dried shell with a power- 
ful lens ; the shell should be wetted with spirit and examined with a 
lens as powerful as Hartnack’s No. 4 objective. 


Renal Organs of Embryos of Helix-*—P. de Meuron describes 
the primitive renal organs of Heljx as arising from ectodermal invagi- 
nations, and not as being mesodermal in origin as are, according 
to Rabl, the kidneys of the aquatic Pulmonata. The walls of the 
organ are formed by large cells, with enormous nuclei, which are set 
in a radiate fashion round the central canal of the tube; some of 
the cells become of a particularly large ‘size, as in the forms studied 


* Comptes Rendus, xcviii. (1884) pp. 693-5. 
Ser. 2.—Von. IV. 5.0 


730 SUMMARY OF CURRENT RESEARCHES RELATING TO 


by the German embryologist. The internal end of the organ is very 
difficult of detection among the mesodermal cells by which it is 
surrounded; however, there appears to be an orifice which is pro- 
vided with vibratile cilia, essentially similar to what has been seen by 
Fol in the aquatic Pulmonata, and by Jourdain in slugs. 

The primitive kidney does not as in Bithynia (Sarasin) appear to 
have any relation to the velum. The permanent renal organ seems 
to be formed from an ectodermal invagination, and a mesodermal 
growth. The author suggests that the pericardiae cavity is the 
cavity of s somite, and that another is indicated by the primitive 
kidney which is the excreting organ of the anterior, as is the 
permanent kidney of the posterior somite. 


Nervous System of Parmophorus australis.*—M. Bontan de- 
scribes the nervous system of the Gasteropod Parmophorus australis, 
specimens of which were collected near Sydney, as being similar in 
its main features to that of _Haliotis,as described by Lacaze-Duthiers. 
The line of papille between the foot and the first fold of the mantle, 
is the homologue of the festooned border of the collarette of Haliotis. 
This row of papille forms part of the mantle, and cannot be referred 
to the foot. The study of Parmophora, in which the nervous centres 
are more separated than those of Haliotis, leaves no doubt in this 
respect. 


Organization of Haliotis.;—H. Wegmann considers that Haliotis 
has many points in common with the Acephala. Thus :—There is a 
coecum between the stomach and the intestine. The digestive tube 
is ciliated throughout its greater portion. There are the same con- 
nections between the liver and the digestive tubes as in the Lamelli- 
brancks. 

A series of organs, such as the renal organ, the auricle, and the 
gill, are in pairs instead of being odd. Two rudimentary gills, with 
the two that are developed, make up the four of the Acephala. The 
cardiac ventricle is traversed by the rectum. Two arterial passages 
arise from the two extremities of the heart. The venous circulation 
is in its fundamental characteristics that of the Acephala, and the 
position of the right renal organ between the branchie and the system 
is especially important. The structure and relationships of the renal 
organs are essentially the same in the two cases. There is also a 
remarkable simplicity in the genital apparatus; a complete absence 
of accessory glands and copulative organs; and a singular connection 
with the right renal organ, as in many of the Acephala. 


Absorption of the Shell in Auriculide.{—Crosse and Fischer 
illustrate and describe the peculiar absorption of the inner parts of 
the upper whorls of the shell in this family, and also in the genus 
Olivella. These animals appear to have the power of dissolving 
entirely the internal partitions of the shell, from a point some distance 
inside the aperture to the very apex. The only exception in the 


* Comptes Rendus, xeviii. (1884) pp. 1385-7. { Ibid., pp. 1387-9. 
{ Journ. de Conchyl., xxii, (1883) p. 3. Cf. Science, ii. (1883) pp. 663-4. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 731 


family Auriculide is the genus Pedipes, in which the partitions were 
found intact. The absorption is not always complete, nor are tke 
same parts invariably missing. Complete absorption was observed 
in Melampus, Auricula, Blauneria, Marinula, Tralia, Alexia, Monica, 
Plecotrema ; only partial absorption in Cassidula and Scarabus. The 
case of Olivella is more remarkable, since the allied groups Oliva, 
Ancillaria, &c., do not, according to the authors, present this 
peculiarity at all. Tryon, however, observes * that in Oliva reticularis 
he has found the walls absorbed away, so that very little of the sub- 
stance remained, and considers it probable that all shells with close 
volutions are in the habit of absorbing them internally. It is 
certainly the case with many of them. 


Development of the Digestive Tube of Limacina.{—S. Jourdain, 
having reminded us that the first indication of the pharyngeal 
vestibule of the Limacina appears as an invagination of the vitelline 
mass, and that, later, another invagination, which corresponds to the 
anal opening, appears in the middle line, between the two external 
openings of the segmental organs, now tells us that the base of the 
pharyngeal invagination is continuous with a cavity, the walls of 
which are mesodermal and are lined by endodermal cells. The diges- 
tive tube has, at this period, the form of a sac ending in a spherical 
diverticulum, which will become the gland that is incorrectly spoken 
of as the liver. This gland has at first a mesodermal and an endo- 
dermal origin; the framework being formed of mesoderm, and the 
secreting tissue of endoderm. The hepatic tissue is filled with a 
finely granular fluid, which is coagulated by heat, alcohol, or nitric 
acid, but does not lose its tramsparency ; it is a kind of secondary 
yolk, the quantity of which increases rapidly during the early periods 
of embryonic development, and which fills the digestive tube. It 
probably arises from the elaboration of the albumen of the egg and 
is digested by the embryo during its development. 

The internal wall of the alveoli of the hepatic sac gives rise to 
cells by budding; these cells gradually take on the characters of the 
secreting elements of the liver, so that each alveolus becomes a lobe 
of the hepatic organ. This organ ought not to be called a liver: it 
is only a diverticulum of the stomachal portion of the intestinal tract. 
It performs so many functions that it would be better spoken of as a 
chylific gland. Moreover, its mode of development may explain the 
bizarre forms that it sometimes attains, as for example, in the 
Eolidiw, where we may suppose that each of the alveoli of the organ 
became isolated, acquired a great size, and took the form of the varied 
appendages which are found in those Gastropoda, 


Molluscoida. 


Simple and Compound Ascidians.,—W. A. Herdman is unable 
to find a single satisfactory character by which to distinguish simple 
from compound Ascidians. Reproduction by gemmation and the 

* Man. Conch.: Olivella, p. 64. 
+ Comptes Rendus, xeviii. (1884) pp. 1553-6. 
~ Nature, xxix. (1884) pp. 429-31. 
a oY 


732 SUMMARY OF CURRENT RESEARCHES RELATING TO 


formation of colonies in the latter group will not hold, since it is 
possible to pass from Ciona—a typical simple Ascidian—to Distoma 
and the very heart of the compound Ascidians through the following 
series of forms, which shows a perfect gradation of these characters :— 
Ciona, Rhopalea, Ecteinascidia, Clavelina, Diazona, Chondrostachys, 
Oxycorynia, Distoma. The formation of common cloacal cavities, 
canals, and apertures cannot be considered as a diagnostic feature of 
the compound Ascidians, as there are forms considered by all autho- 
rities as Synascidie, such as Chondrostachys, Diazona, Distoma, and 
others, in which the atrial apertures of the Ascidiozooids open inde- 
pendently on the surface of the colony, and no common cloaca is 
formed. 

The characters taken from the condition of the test, break down 
like the others. In the first place, in passing along the series of 
forms connecting Ciona and Distoma, we encounter all stages between 
a distinct test or tunic for each individual, and a common mass in 
which a number of Ascidiozooids are imbedded. And secondly, the 
remarkable group “ Polystyele” presents many of the characters of 
highly differentiated simple Ascidians (the Cynthiid) along with the 
supposed Synascidian feature of a colony composed of many Ascidio-. 
zooids completely buried in a common test. 


Digestion in Salpa.*—Dr. C. 8. Dolley combats the view of Korot- 
neff as to the existence of a large amceboid cell or plasmodium in the 
cesophagus or stomach of Salpa which carries on a form of parenchy- 
matous digestion of the food passing the resulting chyle into the 
walls of the intestine by means of its pseudopodia. 

Dr. Dolley has observed the appearance in the intestines of Salpa, 
which had been described by the Russian author, but he suggests an 
entirely different interpretation. In Salpa we find a large branchial 
sac, representing the true pharynx, at the posterior portion of which 
is the stomach. The endostyle, or thickened bottom of a fold or 
groove of the branchial sac, throws out a supply of mucus, which 
covers the surface like a curtain, and in which nutritive particles 
finding their way into the animal are imbedded. The food is carried 
back by cilia, and the mucous sheet is wound up into a thread, which 
can be traced into the cesophagus, and from there to the stomach. 
This mucous exudation is the ameeboid cell of Korotneff. 


Fresh-water Bryozoa.t—K. Krapelin has been able to find, in 
the neighbourhood of Hamburg, examples of all the genera (except 
perhaps Lophopus) of Bryozoa that are known to inhabit the fresh 
waters of Europe. In addition to these he found large masses formed 
by colonies of Pectinatella magnifica, described by Leidy as living 
near Philadelphia. In this genus, in Cristatella, and possibly also 
Lophopus, the statoblasts are set free on the death of the colony. 
The author asks for the assistance of correspondents for the purpose 
of making a more complete investigation into the biology and geo- 
graphical distribution of these animals. 


* Proc. Acad. Nat. Sci. Philad., 1884, pp. 113-5. 
t Zool. Anzeig., vii. (1884) pp. 319-21. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 733 


Supposed new species of Cristatella.*—E. Potts describes the 
discovery of aggregations of colonies of a species of Cristatella (C. 
lacustris) apparently differing from C. mucedo of Europe and C. Ide 
and C. ophidioidia of America. He considers it to be at least as 
clearly differentiated from any of the other species as they are from 
each other, though probably, as the differences existing amongst them 
are not considerable, all should be merged under C. mucedo. 


Arthropoda. 
a. Insecta. 

New Type of Elastic Tissue, observed in the Larva of Eris- 
talis.| —H. Viallanes has directed his attention to the curious 
movements of the respiratory tube which is found at the end of the 
body in the larve of Hristalis. It is formed of a number of cylinders, 
which can be shortened or elongated at the will of the animal: the 
elongation is effected by the contractions of the body, by means of 
which fluid is driven into it, and its shortening by special muscles 
and internal elastic bands. ach of these elastic bands is formed by 
a single cell, which is so constructed as to act as a piece of caout- 
chouec. The cell is fusiform in shape, and, while one of its extremities 
is attached to the neighbouring integuments, the other is prolonged 
into a process which is fixed to the inner face of the respiratory tube. 
The cell and its prolongation are invested ina membrane, which is of 
some thickness, but is very elastic. At the centre of the cell there is 
a very large spherical nucleus, which is surrounded by a quantity of 
protoplasm, which is also found in the prolongation. Within the cell 
itself there is developed a long elastic fibre, similar in its physical 
properties to those seen, for example, in the cervical ligament of a 
mammal; it is folded a large number of times around the nucleus, 
and passes in a straight line through the prolongation of the cell, to 
the extremity of which it is attached; by the other it fuses with the 
protoplasm of the cell. When the cell is drawn out the coiled 
portion becomes unfolded. 

The facts detailed are of interest, as proving the high degree of 
complexity that may be attained within the limits of a single cell, 
and as throwing a new light on the morphology of elastic tissue, 
since they show that this may be, as in vertebrates, developed in the 
intercellular substance, or, as in Fristalis, in the protoplasm itself. 
It may be noted that striated muscular tissue presents analogous 
variations. 

It would seem, then, that the same tendency obtains in elastic as 
in muscular tissue; in both cases, perfection is attained by parts 
leaving the protoplasm of the cells to which they primitively be- 
longed, and, by becoming intercellular, being converted into the 
undivided property of neighbouring cells. 

Submaxillary of the Jaw of Mandibulate Insects.{—J. Chatin 
retains the name of submaxillary for the part of the buccal apparatus 


* Proc. Acad. Nat. Sci. Philad., 1884, pp. 193-9 (1 pl.). 
+ Comptes Rendus, xeviii. (1884) pp. 1552-3. 
t Ibid., xcix, (1884) pp. 51-3. 


734 SUMMARY OF CURRENT RESEARCHES RELATING TO 


so named by Brullé, and called the cardo by Kirby and Spence. 
Oligotoma Saundersii is taken as the starting point, and its sub- 
maxillary described as being a small transverse piece slightly grooved 
on its inner surface. Cdipoda cinerascens has the same part provided 
with several deep articular cavities. In Decticus the organ is still 
more modified. In Gryllus domesticus it is strongly, and in Phasma 
japetus feebly articulated. In Maniis religiosa it is developed in a 
vertical direction, and has the appearance of some maxille. In 
Hydrophilus piceus the different portions of the organ are profoundly 
modified. ‘The author considers that the descriptions which he gives 
are sufficient to show the interest which attaches to the morphological 
study of the submaxillary, and the changes undergone by a part which 
has been too often misunderstood, but whose correct interpretation 
is necessary in a comparative study of the appendages of the 
Arthropoda. 


Structure and Function of Legs of Insects.*—F. Dahl ascribes 
our ignorance of the structure and functions of insects’ legs to the 
fact that on the one hand most entomological works are of a purely 
systematic character, and that, on the other, anatomists have chiefly 
busied themselves with the axial parts only; in fact, Strauss- | 
Durckheim, Newport, Burmeister, and Graber are the only authors 
to whom Dahl makes reference in his introduction. 

The constancy of the number of six is probably to be explained 
as being in relation to the function of the legs as climbing organs; 
‘one leg will almost always be perpendicular to the plane when the 
animal is moving up a vertical surface; and on the other hand we 
know that three is the smallest number with which stable equilibrium 
is possible; an insect must therefore have twice this number, and the 
great numerical superiority of the class may be associated with this 
mechanical advantage. ‘This theory is not weakened but rather 
supported by the fact that the anterior pair of legs is rudimentary 
in many butterflies, for these are almost exclusively flying animals. 

The author describes in some detail the arrangements of the 
muscles of the legs; the nerve-cord supplying them is pretty stout, 
and the large number of filaments sent to the joints of the tarsus 
lead to the supposition that these have a tactile function ; the nerve- 
fibres are seen to enlarge into thick spindle-shaped ganglia. There 
are two tracheal trunks. 

The prime function of the legs is locomotor, and insects move 
through gaseous, fluid, and solid media. The last is seen in fossorial 
forms, of which Gryllotalpa may be taken as the type; here some of 
the joints are flattened out and provided with teeth, and the muscles 
are well developed. In some cases legs of a fossorial type are 
possessed by insects which move on the ground, but the larve of 
which are subterranean in habitat. The water-beetles and aquatic 
Rhynchota have the legs converted into swimming organs; they are 
widened out into plates and provided at the sides with movable hairs, 
which are directed slightly backwards. The median pair of legs in 
Corisa is provided with two very long hooks, the function of which is 


* Archiv f. Naturg., 1. (1884) pp. 146-93 (2 pls.)- 


ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 735 


to fix the animal at some depth among the water-plants, and so to 
prevent its floating upwards. 

In the aerial forms we have first to notice those that move on the 
surface of the water; in these the legs are often provided with con- 
siderable enlargements of the tracheal trunk, by means of which they 
are enabled to float. Others have very long legs by which they can 
balance themselves and extend over a large surface of the water; the 
lower surface of the tarsal joints, or that which is in contact with 
the water, is provided with thick hairs. In some Diptera hairy lobes 
are developed. Arrangements for climbing are very widely dis- 
tributed, and are very various in character; the most common are 
hooks which by their sharp tips are able to enter the smallest 
depressions and so obtain a firm hold; sometimes they are cleft and 
are thus adapted to hold on to fine branches; sometimes they are 
pectinate and enabled to catch hold of fine hairs. 

In very many cases there are organs of fixation; in the locust 
they have their chief mass made up of a large number of free flexible 
rods (not tubes). The periphery is occupied by scales which corre- 
spond in number to the rods, with which they appear to be connected 
by fibres; the space between the rods is filled with a fluid. Below 
these are groups of spindle-shaped cells which appear to be glandular 
in character. The fixing surface of the Hymenoptera, Neuroptera, 
and Lepidoptera consists of an unpaired lobule placed between the 
hooks ; their structure is most complicated in the first-named order. 
Observations on Vespa crabro did not result in the detection of any 
space which could be regarded as a vacuum. The lower surface of 
the lobule is soft and almost smooth; a few short hairs may be 
developed at its base; below this is a hard chitinous mass with 
stronger hairs. The upper surface is either covered with hairs or is 
finely folded. Near the base is a chitinous plate carrying a pair of 
strong sete. Within is an elastic bar which is rolled up in a con- 
dition of repose ; when extended it brings the lobule into contact with 
the surface on which the insect is standing. ‘There are no well- 
developed gland-cells. After descriptions of other modes of fixation 
the author gives the following table. 


A. Organs of attachment at the end of the foot. 


a. Without fixing hairs ee, “sey | 00st a6. aia ge Pe ae ee 
Forficula. 

8. With fixing hairs ve {Centr 
Sialis. 


B. Organs of attachment between the hooks. 
a. A distinct median lobe. 
a. The median lobe with chitinous arches, 
1. Secondary in addition to the median lobe Neuroptera. 


2. No secondary lobes .. .. . .. .. Hymenoptera. 
b. No chitinous arches i Tenover 
ipula. 


B. No distinct median lobe. 
a, Thedobes hairy: -;, (Pai acl Be hae pie, 
b. The lobes not hairy .. . «. « #«  #Rhynchota, 


736 SUMMARY OF CURRENT RESEARCHES RELATING TO 


The legs may, further, have a sexual function as attaching or 
holding organs; or, as in Mantis religiosa, Nepa cinerea, &c., they 
may be of use in seizing prey; and, finally, they may be used as 
cleansing organs. The legs in ants may be seen to be pectinate, an 
admirable arrangement for forms that live in dust and earth; they are 
often specially adapted for cleansing the proboscis, and for other 
functions for an account of which we must refer to the paper itself. 


Organs of Attachment on the Tarsal Joints of Insects.*— 
G. Simmermacher first takes up the case of sexual organs of attach- 
ment in the Coleoptera; where the males have some of the tarsal 
joints more or less remarkable on account of their widened form, and 
for the possession on the lower stirface of stickers which are visible to 
the naked eye. The differences between males and females are best 
seen in the Dyticid#, where the first three tarsal joints of the first 
pair of limbs are distinguished from those that succeed them, on 
account of their greater breadth ; those of the second pair are a little 
less remarkable. The suckers that are developed belong to the group 
of modifications which were associated together by Plateau under the 
head of “cupules sessiles,” but the author finds that the large 
suckers have a stalk, and they are, further, distinguishable from the 
smaller suckers by the presence of better developed and more 
numerous ridges. The stalk is traversed by a canal. The disposition 
of the suckers on the joints is described: 

The tarsi are moved by a strong muscle, the long axis of which is 
parallel to that of the foot; it is attached to the chitinous exoskeleton 
at every joint, and consists of several muscular fibrils, through which 
pass branches of the tracheal system; the muscle is attached to the 
stalk of the sucker, the movement of which is, therefore, under the 
control of the will. The suckers are to be found on the tarsi of the 
males of all the twelve génera of Dyticide living in Germany; 
the differences seen are found to be constant in genera and species; 
such differences as obtain are due to (a) either the tarsal joints of 
the first and second pair of feet are partly widened out and beset with 
suckers (Dyticus), or there are suckers on the first pair only (Cybister) ; 
(@) the three tarsal joints on the first pair are very greatly widened 
and rounded, and those of the second are but little altered (Dyticus), 
or, as in Hybius, the first pair of feet are but little altered; (7) the 
suckers are either rounded (Dyticus), or elongated as in Cybister ; 
(6) the suckers on one and the same joint are either all similar, or they 
differ in form or size, or in the form of their joints. A systematic 
description of the organs is given for the different genera. 

Simmermacher is of opinion that the grooves on the wing-covers 
of the female Dyticide have no function in copulation, and in this 
he agrees with the results lately obtained by Dr. Sharp, whose im- 
portant monograph he did not see till the first part of his own work 
had been concluded. 

The Carabide and Cicindelide are next dealt with in the same 
manner. 


* Zeitschr. f. Wiss: Zool., xl. (1884) pp: 481-556 (3 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. rio Yt 


In the second part of the essay climbing organs are dealt with; 
in the Chrysomelide, Hylobiide, Telephoride, and Cerambycida, 
the tarsi, in both sexes, are provided on their lower surface with 
chitinous structures which to the naked eye have the same appearance 
as those which are found in the males only of the families already 
discussed. The groups just mentioned live either in water or on 
leaves or stems, where they move about by means of the tubules 
covering their tarsi, and by the aid of which they can fix themselves 
in various positions. ‘These chitinous structures are always tubular, 
and they are never found on more than the first three joints of the 
tarsi. In the tetramerous forms they are widened out and have a 
distinct orifice, but in the pentamerous Telephoride they end in a 
sharp point. In most cases the tubules pour out a secretion, and it is 
probable that we have here to do with the phenomena not of actual 
attachment by, as it were, glueing, but of adhesion ; the orifice of the 
tubes is directed obliquely, and the tubes are, at this point, extremely 
delicate and flexible, so as to adhere by their lower surface; in this 
adhesion they are aided by the secreted fluid. 

In the Cerambycide there is no secretion, and the tubules are 
merely sucking organs, analogous to those which are found in the 
male Silphide. 

Discussing the Diptera, observations on which have been made by 
a number of naturalists whose results are here compared, the author 
describes the ordinary arrangement (such as is seen, for example, in 
the common house-fly) as consisting of two attaching lobes; between 
these there is a rod-shaped elongated piece, beset with chitinous 
hairs. He does not accept the theory by which the movement of the 
fly along smooth surfaces is ascribed to an alternate fixation and 
separation, but believes in a process of adhesion, aided by a secretion, 
just as in the case of the Coleoptera. The attaching lobes closely 
beset with chitinous hairs are enabled, in consequence of the pressure 
of the foot, to completely lie along any smooth surface; this expels 
the air beneath the lobes, which are then acted on by the pressure of 
the outer air. 

There are a few observations on the Hemiptera, Neuroptera, 
Lepidoptera, Hymenoptera, Orthoptera, and Strepsiptera; and, in 
conclusion, analogous cases are cited from other divisions of the 
animal kingdom ; sucking tubes are seen in the Acinete, ambulacral 
feet in Echinids and Asterids, sucking organs of attachment in Chiton 
and Patella, suckers in the Cestoda and the Hirudinea; Schmidt 
regards the pectines of the scorpion as having a similar function, 
and numerous examples are to be found among Vertebrates. 


Locomotion of Insects on Smooth Surfaces.*—Dr. J. E. Rom- 
bouts writes as follows :— 

“‘T have concluded from my experiments that it is not the pressure 
of the air nor the power of an adhesive liquid that gives flies the 
faculty of running over smooth bodies, but that the power should be 


* Amer. Mon. Micr. Journ., v. (1884) pp. 99-100. From Pop. Sci. Mon, 
May 1884, 


738 SUMMARY OF OURRENT RESEARCHES RELATING TO 


attributed to the molecular action between solid and liquid bodies; 
or, in other words, to capillary adhesion. 

If we examine the under part of the pulvilli with a Microscope, we 
shall see distinctly that it is furnished with numerous hairs, regularly 
distributed. These hairs terminate, at their lower end, in a kind of 
bulb, the form of which varies, whence flows an oily liquid that dries 
slowly and does not harden for a long time. The minute drops left 
on the glass by the hairs may be taken away, even after two or three 
days have passed, without our having to moisten them, by simply 
rubbing a piece of fine paper over them. 

I have devised an apparatus for collecting these drops by cutting 
a hole in a piece of board, over which I fix a glass slide. Turning 
the board over so that the glass shall be at the bottom, I have a little 
cell with a glass floor. With the aid of a piece of paper gummed 
to the wings, I introduce a fly into this cavity in such a manner that 
the pulvilli shall rest upon the floor. Then, putting the board under 
the Microscope with the glass slide uppermost, we have the fly’s feet 
under oureyes. The insect, struggling for liberty, places his pulvilli 
against the glass, and leaves after each effort traces that may be 
observed very distinctly, for they are perfectly visible in a good 
light. 

We may discover, whenever the feet of the fly come again in 
contact with these tracks or minute drops, that they are composed of 
a very liquid substance, for they spread quite readily on the glass. 
We cannot admit, as some naturalists assume, that the liquid can hold 
the club-shaped hair-ends by suction. If this were the case, the ends 
would change shape during the suction, and would take the form of a 
disk. The fly puts its feet down and lifts them up with an in- 
comparable facility that would not exist if the limb were really acted 
upon by the pressure of the air.” 


Organs of Flight in the Hymenoptera.*—Dr. Amans has a further 
paper on flying organs ‘in insects, and in the groups now studied he 
recognizes as constant factors the following. The general form of 
the machine must be a more or less elongated oval, with its widest 
end directed forwards. 'The framework must have a solid floor with 
more or less elastic walls, more or less united behind so as to form a 
fixed transverse pivot-line; the walls must be sustained by a vertical 
column, and there must be a roof movable on these walls around the 
pivot-line, from before backwards and below upwards. The rotation 
is effected by means of the wings. 

The “schematic form of the wing” is that of an elastic triangular 
surface, the breadth of which gradually diminishes from before back- 
wards, and from base to summit, the latter being centrifugal. For 
its articulation the wing must have a double articular surface at its 
point of attachment, and the movable roof must articulate with the 
apex of the angle of the dihedron. The surface in front of the point 
of attachment must be one of pronation, that behind it of supination. 
The motors are (a) forces that are elevating, retracting, and divari- 


* Rey. Sci. Nat., xii, (1884) pp. 482-522 (2 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 739 


cating ; (b) forces antagonistic to the preceding ; (c) propulsive, flexing 
and depressing the anterior plane; and (d) forces which depress and 
propel the posterior plane. The first two of these are inserted into 
the roof and floor, the last two into the base of the wing. The motor 
forces are the voluntary muscles, the actions of which are combined 
with involuntary, that is, elastic forces: of the latter, the chief are 
the resistance of the roof to the curvature caused by the former when 
the wing is depressed, and the resistance of the anterior part of the 
point of support to the flexion due to the muscles of group (c). 

The author bases these conclusions on what he has seen in the 
Orthoptera, Pseudo-neuroptera, and Hymenoptera. 

Poison of the Hymenoptera and its Secreting Organs.*—G. 
Carlet, in opposition to previous observers, finds that the venom- 
producing apparatus of the Hymenoptera is always formed by two 
distinct systems of glands, one of which has a secretion which is 
strongly acid, and the other feebly alkaline. The two systems open 
at the base of the spine, and the combined liquid is always acid. 
Experiments made on the common house-fly showed that the sting of 
a venomous Hymenopteron was always followed by the immediate 
death of the fly, but that the inoculation of the product of either of 
the glands does not result in death, or only in death after a long 
interval. The successive inoculation ‘of the two secretions leads to 
death shortly after the second inoculation, and we may suppose that 
life ceases as soon as the two liquids have mixed. It is then clear 
that the union of the acid and alkaline secretions is necessary for the 
venom to have any fatal effects. 

Development of Cerocoma Schreberi and Stenoria apicalis,t— 
H. Beauregard communicates some facts as to the development of 
certain insects allied to Cantharis; the larve appear to be melli- 
vorous, and it is possible that they may live as parasites indifferently 
in certain Hymenoptera. The larve, contrary to the habits of Epi- 
canta and Macrobasis, as described by Riley, do not live on the eggs 
of Orthoptera. It has been found that the larva of Cerocoma lives on 
the honey of Colletes and of Osmia. 

Other pseudochrysalids found in the cells of Colletes signata, and 
presenting a very regular ovoid form, of a golden yellow colour, and 
enveloped in a very fine iridescent pellicle, were watched through 
the winter, and found in May to commence to undergo a series of 
metamorphoses which ended in the appearance of the adult Stenoria 
apicalis, which was found by Lichtenstein to be, in its earliest stages, 
parasitic on Colletes fodiens. Here, again, therefore, we have evidence 
as to the indifference which these parasites exhibit as to their choice 
of a host. The history of development justifies the separation of 
Stenoria from the true Sitaris. 

Dipterous Larve.{—Dr. F. Brauer has published a valuable mono- 
graph on this subject, the result of ten years’ labour. 

* Comptes Rendus, xcviii. (1884) pp. 1550-1. 


t Ibid., xcix. (1884) pp. 148-51. 
¢ Denkschr. K. Akad. Wiss. Wien, xlvii. (1883) 100 pp. (5 pls.), Of. Amer, 


Natural,, xviii. (1884) pp. 609-11. 


740 SUMMARY OF CURRENT RESEARCHES RELATING TO 


After lengthy remarks on the systematic relations of different groups 
of Diptera, based on the larval characters, he states that the typical, 
inherited feature in the entire group of Dipterous larve appears to be 
the position of the brain, whether it is contained in a head-capsule, or 
free, i.e. far behind the mouth or immediately behind the chitinous 
capsule, supporting some of the mouth-parts, and containing the 
cesophagus. Less important characteristics are then enumerated. A 
very unsafe character is the number of visible body-segments. 

The characters of the dipterous larve in general are laid down and 
the value of the larval characters in classification discussed. A 
tabular view of the nervous systems of the larval as compared with 
the adult Diptera is followed by a section on the character of the 
sub-orders and families which occupies the greater part of the work. 
It is succeeded by short descriptions of a few larva of the families 
Tabanide, Leptide, Dolichopide, and Empide. 


Larve of North American Lepidoptera.*—A. Gruber gives a 
description of the larve of some Papilionidz and Nymphalide ; scanty 
as his material seems to have been, he thinks that the larve before 
him give indications of the possibility of making out the genetic 
relations of the species. 

The first stage of the larve of the Papilionide is distinguished b 
the constant possession of well-developed warts, on which there are 
long sete that give a hairy appearance to the caterpillar. They are 
longest on the most anterior and the most posterior rings of the body 
and a correlation is apparent between the thoracic and the three last 
abdominal segments. After each ecdysis the warts decrease in size, 
and sooner or later disappear altogether; the smallest, or those on 
the median segments, are the first to be lost. The function of these 
warts appears to be that of providing suitable and prominent points of 
attachment for the sete; it is to be noted that the warts are rudi- 
mentary in proportion to the distinctness of the markings on the 
caterpillar. It is these markings that have been seized upon by 
natural selection, and the other characters, which have lost their 
significance, have been gradually suppressed. When the warts do not 
interfere with the markings, as in the case of larve with black trans- 
verse bands, they do not completely disappear until the last ecdysis. 

We may, therefore, suppose that the larve of the Papilionida 
have been derived from forms which were indifferently coloured and 
not strongly marked, and which possessed strong setigerous warts ; all 
the larvee in their first and even in their second stage, resemble this 
hypothetical primitive form. Numerous intermediate conditions are 
to be observed between it and the conspicuously marked forms found 
at the present time, and each larva more or less completely repeats, 
at its ecdyses, the phylogenetic history of its species. 

Further than this, we may suppose that those larve which retain 
their warts longest are the oldest forms, or those that stand nearest to 
the primitive form. 

The Nymphalide present arrangements which are the opposite 


* Jenaisch. Zeitschr. f. Naturwiss., xvii. (1884) pp. 465-87 (2 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 741 


of what are seen in the Papilionide, for, in the first stage, the sete 
are set on inconspicuous elevations of the integument; in the second 
there are conical warts, and these increase in size with each ecdysis : 
the warts of the Nymphalide are, therefore, not inherited, but 
acquired structures; their armature becomes of great importance and 
affects their external form. 

The most primitive sete appear to be those which are long, 
slightly curved, and finely toothed on their margin ; in the course of 
development they become simply smooth or swollen at their base. 

The author hopes that the suggestions he puts forth will be 
examined by those who have access to a larger number of examples, 
and justly remarks that the investigation would be very valuable and 
interesting. 


Drinking Habit of a Moth.*—E. D. Jones describes a remark- 
able drinking habit of a yellow and black Brazilian moth (Panthra 
pardalaria). He found these moths sitting on the wet stones in small 
streams near San Paulo, sucking up the water in a continuous stream, 
and letting it escape in drops from the abdomen. These drops fell at 
the average rate of 50 per minute, and as near as he could judge of 
their size, the total quantity of water which must thus pass through the 
body of the moth in three hours must be a cubic inch, or about 200 
times the bulk of its own body. Mr. Jones speculates on the possible 
meaning of this and asks—* Can it be that the moth extracts nourish- 
ment from minute particles of organic matter contained in the water ?” 
He remarks, however, that the water of the streams appears very clear 
and pure, and notes that the moths seem specially adapted for this 
habit. ‘The tibiz of the hind legs are very thick, and are armed with 
long hairs, which by their capillary action prevent the moth being 
immersed in the water “I have often,” he adds, “seen one of them 
knocked down by a little spurt of water splashing over the stone 
on which it was standing, and it recovered itself almost immediately 
without being wetted in the least,” 


vy. Arachnida. 


Michael’s British Oribatide.|—It would be difficult to say too 
much in praise of this book which the Ray Society are fortunate in 
being able to publish as one of their invaluable series, while this 
Society may congratulate itself in numbering among its active members 
an author who has produced a work which has required so much 
labour and skill and so much perseverance, and which will rank as 
one of the not too numerous standard works in the English language 
devoted to sections of the Invertebrata, The author’s tribute to the 
assistance rendered him by his wife, is an additional justification (if 
any is required) for the resolution which he recently moved for the 
admission of lady Fellows to the Society, 

The classification of the Oribatide is fully dealt with, followed 


* Proc. Lit. and Phil. Soc. Liverpool, xxxvii. (1883) pp. Ixxvi.—vii. 
+ Michael, A. D., ‘British Oribatide,’ xi. and 336 pp. (3 pls.) 8vo. Ray 
Society, 1884. 


' 


742 SUMMARY OF CURRENT RESEARCHES RELATING TO 


by a chapter on their development and immature stages, the observa- 
tions necessary for which were the most laborious part of the author’s 
undertaking, involving the rearing of a large number of the micro- 
scopic animals in confinement, and their careful watching and the 
regulation of their hygrometic conditions every day for months! 
They had indeed to be carried about with him on any journeys. 
Amongst the habits of the Oribatide are enumerated their avoidance 
of light, which increases so much the difficulties of observation, their 
habit of carrying a portion of their cast skins and piling up dirt and 
rubbish on their backs to form an artificial covering, or investing 
themselves with a white substance. From the chapter which gives 
very detailed directions on collecting and preserving, we have already 
made some extracts.* 

The remainder of the book deals with the anatomy of the exo- 
skeleton and internal anatomy (pp. 110-190) and with the description 
of genera and species (pp. 191-327). 31 plates, mostly coloured (some 
of which have appeared in this Journal in connection with Mr. 
Michael’s various papers), illustrate the text. 

A type series of slides has been deposited by Mr. Michael in the 
Society’s cabinet. 

6. Crustacea. 


Stomach of Podophthalmate Crustacea.{—In this important con- 
tribution to our knowledge of the anatomy of the higher Crustacea, 
F. Mocquard, after the ordinary historical review, points out that in 
the Decapoda there are important differential characters, distinguishing 
the Brachyura from the Macrura, but that, as is already known, the 
so-called Anomura belong, some to the brachyurous and some to the 
macrurous type. When we review all the families we find in every 
natural one that the gastric apparatus is arranged on a special and 
characteristic type. 

In the Brachyura the mesocardiac piece is narrow and triangular, 
while the pterocardiac ossicles are elongated and directed horizontally ; 
in the Macrura, on the other hand, the former occupies the whole of 
the transverse line of the superior cardiac wall, while the latter are 
ordinarily shorter than in Brachyura and are set almost vertically. 
Although it is true that the short-tailed forms never present the 
characters seen in the gastric ossicles of the long-tailed, the converse 
proposition does not hold good, for in such Macrura as have under- 
gone some degeneration, the ossicles are formed on almost the same 
type as in the Brachyura. The more detailed account of the differ- 
ences between these two groups are set forth in the paper. 

In passing from the normal Brachyura to the abnormal (or apteru- 
rous Anomura), we observe a certain number of characters inter- 
mediate between what are seen in the Brachyura on the one hand, 
and the Macrura on the other; and it is to be noted that, on a con- 
sideration of nothing but the arrangements of the parts of the gastric 
skeleton, we should ascribe to them that intermediate position which 


* See this Journal, ante, p. 635. + Tbid., p. 500. 
{ Ann. Sci. Nat. (Zool.), xvi. (1884) 311 pp. (11 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 743 


is commonly ascribed to them, after a study of their characters in 
general. 

Notwithstanding the numerous differences presented by different 
groups, in the successive series of degradations which are to be 
detected, it is possible to show that the gastric skeleton is never 
modified except by change in the form or relations of its parts, by 
their coalescence and disappearance ; nothing new is ever added, and 
even when most degraded, the homology of the different parts can be 
asserted almost with certainty. In other words, the gastric skeleton 
of all the podophthalmate Crustacea is constructed on the same plan. 

The author makes some remarks from a systematic point of view, 
and urges that the importance of the characters of the stomach is to 
be explained by the fact that it is not directly subjected to external 
influences, and is much less exposed to the changes which result from 
adaptations to environment than are the external organs. These 
characters then, are of great value in determining the relationships of 
genera with a different external appearance. 

Mocquard describes the arrangement of the muscles which move 
the various ossicles, and facilitates the comprehension of his descrip- 
tion by his figures; he finds that, at the moment when the gastric 
muscles contract the median tooth moves forwards, and the anterior 
ends of the lateral teeth approach one another; when the gastric 
muscles relax the apparatus is brought back to its position of equi- 
librium, by the elasticity of its articulations, and by the action of the 
cardio-pyloric muscle. When the gastric apparatus is acting, the 
food tends to be driven upwards, but its passage is prevented by the 
projections on the urocardiae ossicle. The medio-inferior tooth, 
though with the form, has not the function of a tooth ; its conforma- 
tion has no relation to that of the median tooth, and one of the two 
may vary in form, without the other doing so likewise. 

The author agrees with Cuvier in thinking that the gastric muscles 
are voluntary in nature. 

The concluding chapter deals with the stomatogastric nervous 
system, the knowledge of the distribution of which is thought to 
throw a new light on its physiological activity. While some authors, 
such as Meckel and J. Miiller, have compared it to the great sympathetic 
of vertebrates, others, such as Newport and Blanchard, have compared 
it to the pneumogastric nerve. The latter view can only be justified 
by showing that the stomatogastric system presides over the functions 
of general sensibility and involuntary movement ; as a matter of fact, 
however, in the Crustacea, the fibres that pass to the muscles of the 
cesophagus and labrum are clearly voluntary, and the same is almost 
certainly true of the branches that go to the motor muscles of the ~ 
gastric apparatus, and possibly also of those that supply the dilatators 
and constrictors of the stomach ; some of those that go to the labrum 
seem, moreover, to have a gustatory function. It is possible, how- 
ever, that the different roots of the stomatogastric have different 
functions, and that, when united, they form a mixed trunk more com- 
plex even than that of the vagus after its union with the internal branch 
of the spinal. No observations on this point have as yet been made, 


744 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Significance of the Larval Skin in Decapods.*—H. W. Conn 
discusses the phylogenetic significance of the peculiar structure 
inclosing embryos of Crustacea known as the larval skin. This 
skin being probably of no physiological importance, is therefore 
particularly valuable in its morphological significance. 

A number of new types of larval skin are described (Callinectes, 
Sesarma, Pinnotheres), and it is shown that there is a complete and 
graduated series beginning with a form like Panopeus, where the 
larval skin is a highly complex structure with many feathered spines, 
and ending in a form like Pinnotheres, where the cuticle is nothing 
more than a larval covering with no spines. In general also it is 
found that the more complex larval skin is found in crabs, which 
stand low in classification, while the simple larval covering is found 
in more highly organized Brachyura ; a condition of things just as 
we should expect from the consideration that this structure represents 
the ecdysis of some stage in the crab development earlier than the 
zoea. It is further shown that such an earlier stage was probably a 
protozoea and that we, therefore, have here strong evidence that this 
stage was formerly included in the ontogeny, and therefore in the 
phylogeny of the Brachyura. Finally it is argued that evidence is 
here obtained tending very strongly to show that the Decapod zoea is 
simply a larval form which has neyer been represented in the phylo- 
genetic history of the group, contrary to what has been claimed by 
Miiller, and later in a different form by Balfour. 


New or Rare Crustacea.{—In his 34th article on this subject 
M. Hesse describes five new Crustacea belonging to the order which 
he has called that of the Rostrostomata; like the Siphonostomata, 
they are found on the skins of the Squalide, but, unlike them, they 
have not a rigid tubuliform mouth by means of which they can 
penetrate the thick skin; the mouth is rather obtuse and soft, and 
the animals, therefore, make their way into the branchial cavity, where 
they are sheltered and early obtain a rich supply of food. 

The new species, of which the females are alone known, are called 
Kroyeria galei vulgaris, Eudactylina squatine angeli, Eudactylus 
musteli levis, E. charcharie glauci, and Pagodina charcharie glauci. 
The author concludes with some observations on the systematic 
position of these species. 
: Vermes. 


New Type of Hirudinea.t{—MM. Poirier and A. T. de Rochebrune 
describe a new type of Hirudinea which they found attached not 
only to the mucous membrane of the mouth of Crocodilus vulgaris, 
Cataphractus, and Leptorhynchus, but also on the lingual papille of 
Cymnoplax egyptiacus, and in the pouch of Pelicanus and Onochrotalus. 
In external appearance it has a general resemblance to Branchiobdella. 
Attached to the very delicate rectum are four pairs of very sinuous 


* Stud. Biol. Lab. Johns-Hopkins Univ., iii. (1884) pp. 1-27 (2 pls.). Cf. this 
Journal, ante, p. 226. 

+ Ann. Sci. Nat. (Zool.), xvi. (1884) 18 pp. (8 pls.). 

{ Comptes Rendus, xcviii. (1884) pp. 1597-1600. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 745 


tubes, which are set between the dorsal surface of the animal and 
-the ceca. The appendages of the digestive tube are continued into 
the branchiz, and the tract is also remarkable for the possession 
of large unicellular glands with finely granular contents; these form 
the salivary glands. 

The male generative apparatus is composed of four pairs of ovoid 
testicles, which are placed in the last four branchiate segments; the 
efferent ducts unite, on leaving the epididymis, into a short azygos sper- 
matic canal, which passes into a large muscular pouch, into which the 
very large penis can be retracted. The female organs consist of a pair 
of very long pyriform ovaries, and of two delicate oviducts which pass 
into an inconspicuous uterus. The circulatory system presents some 
remarkable characters. There is no dorsal vessel, but there are two 
pairs of lateral vessels, which are superposed and send branches into 
the branchial outgrowths; the superior lateral vessels, which may be 
considered as being arterial, communicate with one another in each 
ring by an annular vessel which sends fine ramifications to the surface 
of the skin; posteriorly, these two lateral canals bifurcate and unite 
by the branches thus formed ; they here give off a number of ramifi- 
cations which extend over the lower surface of the sucker, and pass" 
into a double circular vessel which extends round the edge of the 
sucker. There is a median ventral vessel which envelopes the nervous 
system and gives rise anteriorly to a ring which communicates with 
the lateral vessels, and posteriorly to a number of branches which 
open into the vessels of the sucker. The nervous system has a close 
resemblance to that of Clepsine; there are two very large, cup-shaped 
orange-coloured eyes. The integument, especially in the anterior 
region, is very rich in glandular cells. 

The new genus to be instituted is called Lophobdella, and the 
species L. quatrefagesi ; it is found in Senegambia and the rivers of 
Africa. Its peculiarities require the formation of a new family, to 
be called the Lophobdellide, and placed near the Rhynchobdellide. 


Structure of the Branchie of Serpulacee.*—Dr. L. Orley gives 
a detailed account of the histology of the gills in the Serpulacee. 
His results may be stated as follows :— 

In Serpula the gill-threads are borne upon two curved lamellar 
processes, one on cither side of the head; these are united by a cross 
piece; one or two of the gill-threads are modified into a stalked 
opercular plate; this latter in some species serves as a chamber for 
the development of the ova, and is generally regarded as serving to 
close the tube of the animal when it is retracted. Its structure, 
however, points to the conclusion that it may also serve as a respi- 
ratory organ (the other gill-filaments with which it is homologous 
being chiefly tactile). It receives a vast number of capillaries which 
branch repeatedly towards the distal end of the “cup,” and end in 
ampulla-like dilatations; the advantage of such a structure to 
the animal must be great, since it is enabled to protect itself by 
closing the operculum, and at the same time the process of respiration 


* MT. Zool. Stat. Neapel, v. (1884) pp. 197-228 (2 pls.). 
Ser. 2.—Von. IV. 8D 


746 SUMMARY OF CURRENT RESEARCHES RELATING TO 


can go on; the operculum may perhaps have been formed by the 
concrescence of a series of gill-branches arranged in a circle round 
the tip of the gill-filament. 

In Sabella the gill-filaments differ from those of Serpula by the 
presence of a cartilaginous rod and a portion of the longitudinal 
muscle-layer of the body which is prolonged into them in close con- 
nection with this skeletal rod. 

The paper concludes with a discussion concerning the homologies 
of the gills in Serpulacee with the gills of Vertebrata, which is 
believed to exist by some; the author, however, does not con- 
sider that there is any homology or even analogy between the two 
structures. 


Structure and Development of Fresh-water Dendrocela.*—The 
studies of J. Jijima are based chiefly on Dendrocelum lactewm, 
Planaria polychroa, and Polycelis tenuis (n. sp.). Commencing with 
a description of the cilia, he states that, in adult forms, these are not 
developed over the whole surface of the body, but are absent from 
certain regions; they are particularly well developed at two points at 
the anterior margin of the head, where they form a tuft of long and 
constantly moving hairs; their function would appear to be sensory.. 
Some shorter immobile cilia are found on the median portion of the 
cephalic margin, and among these there are some which are twice as 
long, and either stand separately or arise from a common base; they 
may be regarded as comparable to sete. The absence of cilia from 
the sides of the body may be ascribed to the influence of parasitic 
Protozoa. It would seem that the cilia on the back of the Geoplana 
and other terrestrial Triclades, are more delicate than those on the 
ventral surface, and are, therefore, more easily destroyed in the 
process of preservation. 

The author was, like Kennel, unable to detect the unicellular 
epidermal glands seen by Moseley, and is led to doubt their presence ; 
a certain relation was observed between the rhabdites and the 
characters of the cells of the epidermis; the smaller size or number 
of the former being associated with a greater wealth of finely glanular 
protoplasm in the latter. Jijima finds that there is a very re- 
markable relation between the cells and the basal membrane on 
which they are placed; for the former give off a number of fine pro- 
cesses; these are best studied in Planaria polychroa, where they appear 
to be formed by fibrils, which are nothing else than direct proto- 
plasmic processes of the cells of the epidermis; there is little doubt 
that there is an organic connection between the epithelium and the 
interior of the body. 

The rhabdites, which are described in some detail, do not seem to 
be imbedded in the epithelium, but in the peripheral cells of the 
mesenchym. Lach cell gives rise to several rhabdites, which are 
at first small and round, but which soon elongate. When they have 
reached their definite size they break through the cell-wall, which 
appears at last to be absorbed, and wander through the connective 


* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 359-464 (4 pls.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 747 


tissue and the basal membrane, either separately or by groups, into 
the epidermal cells, where they take up their definite position. There 
appear to be a larger number of rhabdites in more sensitive than in 
less sensitive parts of the body. The basal membrane is more or less 
well developed in all Turbellarians. The characters of the musculature 
are discussed in detail, and the differences between the three species 
examined are pointed out. 

The mesenchym contains imbedded in itself unicellular glands, 
which are most numerously developed behind the brain, and above 
and below the enteric canal. Their function is either mucous or 
salivary ; but it is by no means certain that the latter are comparable 
to the similarly named glands of higher animals. In young embryos 
the space between the epidermis and the enteric epithelium is occu- 
pied by a solid mass of connective-tissue cells, which are partly 
massed into syncytia, and are partly separated by cell-boundaries. In 
the adult the arrangement is very different, owing to the appearance 
of a larger number of pseudo-ccelomic spaces, which communicate with 
one another, and force the nuclei away from one another, and so give 
rise to branching cells of connective tissue and a general appearance 
of reticulation. In the living animal the lacunar spaces are probably 
filled with the so-called perivisceral fluid, which possibly serves as a 
carrier for the nutriment prepared within the enteric cells. Dendro- 
celum lacteum has, as its name implies, none of its connective tissue 
pigmented, as is the case in a number of other forms. 

The author confirms in many points the descriptions given by his 
predecessors as to the characters of the digestive organs; in D. 
lacteum he finds that there are 26-34, in Pl. polychroa 22-28, and in 
Pol. tenuis 15-19 pairs of lateral branches to the intestine, of which 
10-15, 9-13, and 4-6 respectively belong to the primary trunk of the 
gut. All but those at either end branch dichotomously. His account 
of his own observations on the excretory organs is prefaced by a 
statement of what has been done by recent observers; the point to 
which he himself directs express attention is the undoubted fact of 
the presence of cilia in the lumen of certain capillaries; in the 
median part of the body they are best developed, and take a coiled 
course; their movement is definite in direction, and these ciliated 
vessels have nothing to do with the ciliited infundibula. Many of 
these vessels are so fine that, were it not for their cilia, they would 
be invisible. The ciliated infundibula are not numerous in, at any 
rate, young specimens, and are often widely separated from one 
another. The presence of excretory vacuoles was recognized, and 
they were seen to be, like the vacuoles of the Protozoa, clear during 
life; they give some indications of containing products of uric 
excretion. 

After a very detailed description of the generative organs, the 
nervous system is taken up. This was studied by the light of Lang’s 
investigations, the general results of which are fully confirmed. 
Jijima had no difficulty in convincing himself of. the existence of a 
plexus of fine nerves on the dorsal surface, lying just beneath the 
inner longitudinal fibres of the dermal musculature. As in other 


oD 2 


748 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Platyhelminths, there are two longitudinal nerve-trunks which unite 
posteriorly, after gradually increasing in size. The transverse com- 
missures go directly from one trunk to the other, and often branch 
and anastomose with their neighbours. Both the commissures and 
the lateral nerves give off a number of fine branches ventrally. The 
brain of Planaria polychroa stands at a lower level than that of D. 
lacteum or Pol. tenuis, owing to the want of concentration of the 
sensory nerves into anterior cerebral lobes. The eye of P. polychroa 
is described as consisting of a pigment-goblet, an optic cone, and an 
optic ganglion. The first is formed of compact pigment-granules, 
and has its orifice directed outwards and upwards. Anteriorly to this 
opening there is a collection of nervous substance, surrounded by a 
number of nuclei, which appear to belong to ganglionic cells. 

The author was unable to observe the impregnation of the ovum, 
and thinks it likely that the spermatozoa are to be found in the 
albuminous fluid of the cocoon. Directive corpuscles were not 
detected, probably because the ova have no investing membrane, so 
that their presence was obscured by the contents of the cocoon. ‘The 
layer of fused cells, which early becomes developed, seems to be due 
to the metamorphosis of the peripheral cleavage-spheres. The em- 
bryonic pharynx is formed by the elongation of some of the endo- 
dermal cells, which become converted into muscular cells, and surround 
a central group of cells, which soon afterwards begins to make its 
way to the surface; clefts appear in this mass and lead to the 
gradual appearance of a lumen. This pharynx is only provisional, 
and is at about the twentieth day replaced by the one which is 
possessed by the adult. The author has, unfortunately, no ob- 
servations to record on the mode of development of the excretory 
organs, or of the finer parts of the nervous system. 


Classification of the Rotifera.*—Dr. C. T. Hudson points out 
what seem to him to be the chief faults in the systems of Ehrenberg, 
Dujardin, Leydig, and Bartsch, and proposes the following arrange- 
ment of the Rotifers in well-marked and fairly natural groups. 


ORDER I. RHIZOTA. 


Fixed forms; foot attached, transversely wrinkled, non-retractile, 
truncate. 


Fam. 1. FLoscunARIADZ. 


Mouth central; ciliary wreath a single half-circle above the 
mouth ; trophi uncinate. 


Fam. 2. Menicertapz. 


Mouth lateral; wreath two marginal curves nearly surrounding 
the head, with mouth between; trophi malleo-ramate. 


* Quart. Journ. Micr. Sci., xxiv. (1884) pp. 335-56 (15 figs.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 749 


ORDER II. BDELLOIDA. 
That swim and creep like a leech; foot retractile, jointed, tele- 
scopic, termination furcate. 
Fam. 3. PHILODINADZ. 


Trochal disk two transverse circular lobes ; wreath two marginal 
curves on each lobe with mouth between ; or trochal disk of one lobe 
ventrally furred with cilia; trophi ramate. 


ORDER III. PLOIMA. 
That only swim. 


* Tlloricated. 
Fam. 4. Hypatinapz@. 


Trochal disk transverse with ciliated prominences; wreath double ; 
trophi malleate ; brain small, not sac-like ; foot furcate. 


f 


Fam. 5. SynonmrTapz. 
Trochal disk rounded ; wreath of interrupted curves, surrounding 
the head ; trophi virgate; foot absent, or minute. 
Fam. 6. Norommatapz. 
Trochal disk oblique; wreath of interrupted curves and clusters ; 
trophi virgate or forcipate ; brain large, sac-like ; foot furcate. 
Fam. 7. TRIARTHRADZ, 


Trochal disk transverse ; wreath single, marginal ; trophi malleo- 
ramate; foot absent. 


Fam. 8. ASPLANCHNADA. 


Trochal disk rounded ; wreath single, marginal ; trophi incudate ; 
intestine, anus, and foot absent. 


** Toricated. 
Fam, 9. Braonwionrp™. 


Trochal disk transverse with ciliated prominences ; wreath single, 
marginal ; trophi malleate ; lorica entire, simple; foot transversely 
wrinkled, wholly retractile, two-toed or absent. 


Fam. 10. Preropinapz. 


Trochal disk two transverse circular lobes; wreath on each 
double, marginal ; trophi malleo-ramate ; foot transversely wrinkled, 
wholly retractile, ending in a ciliated cup. 


750 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Fam. 11. EvoHLAnipa. 


Trochal disk rounded ; wreath in interrupted curves and clusters ; 
trophi sub-malleate or virgate; lorica im two parts, meeting in a 
furrow, or entire with additional pieces : foot jointed, feebly retractile, 
not telescopic or transversely wrinkled—furcate or stylate. 


ORDER IV. SCIRTOPODA. 
That swim with their ciliary wreath, and skip by means of hollow 
limbs with internal locomotor muscles. 
Fam. 12. PepAionip™. 


Trochal disk transverse ; wreath two marginal curves with mouth 
between ; trophi malleo-ramate; foot replaced by two posterior 
ciliated processes. 


GENERA.* 
1. Fuoscunariapz .. Floscularia, Stephanoceros. 
2. MeuicertaDH .. Melicerta, Limnias, Micistes, Cephalosiphon, 
Lacinularia, Megalotrocha, Conochilus. 
3. Painopinapbz = ..._~—«- Philodina, Rotifer, Callidina. 
4, HyDATINADE .. Hydatina, Rhinops. 
5. SyncpmTapH .. Syncheta, Polyarthra. 
6. Norommatapz .. Notommata, Diglena, Furcularia, Scari- 
dium, Pleurotrocha, Distemma. 
7. TriartHraDz .. ‘Triarthra. 
8. ASPLANOHNADZ .. Asplanchna. 
9. Bracnionipz .. Brachionus, Noteus, Anurea, Sacculus. 
10. Preropinapz .. Pterodina, Pompholyx. 
11. EvcHLanipz .. Huchlanis, Salpina, Diplax, Monostyla, 
Colurus, Monura, Metepidia, Stephanops, 
Monocerca, Mastigocerca, Dinocharis. 
12. Pepauionipz .. Pedalion. 


Echinodermata. 


Constitution of Echinoderms.t—C. Viguier, after a reference to 
the belief that Echinoderms are radiated animals, discusses the 
view propounded by Duvernoy and forcibly enunciated by Hackel, 
against which he has already raised some objections, and side by side 
with which he now pits the doctrine of Perrier taught in his work 
on ‘ Colonies Animales.’ According to the view of Perrier, the Echino- 
derm is indeed a colony, but, instead of being formed of five equiva- 
lent individuals (antimeres), it consists of five reproductive individuals 
grouped around a nutrient individual; these may coalesce in various 
proportions. All Asteroidea are fragile, and all enjoy the power of 


* “The principal ones; several of Ehrenberg’s are omitted for various reasons 
that cannot here be detailed, and the genus Notommata, though the name is 
retained, is here supposed to have lost a large number of Ehrenberg’s species.” 

+ Comptes Rendus, xcviii. (1884) pp. 1451-3. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. Tol 


repairing broken arms; this rupture is often followed by a process of 
reproduction, numerous cases of which are already known. These 
facts may be as easily explained by the theory of Hackel as by that 
of Perrier, but there are others which can only be explained by the 
latter. 

The hard parts around the mouth are, it is well known, very 
difficult to homologize with the ambulacral and adambulacral ossicles 
of the arms; but it is necessary to do this, if we regard the disk as 
nothing more than a fused part of each of the arms. On the other 
hand if either disk is an independent piece no homology is possible. 

We sometimes find specimens in which a broken arm becomes 
bifurcated at its free end ; if the buccal angles were merely formed by 
the union of the pieces of two neighbouring arms (as ought to be the 
case on Hiickel’s theory) it is difficult to see why the angle of bifurca- 
tion should not be formed in just the same way. On the other hand, 
if the peristomial skeleton belongs to a central individual it is evident 
that an arm could not produce along its own course pieces similar to 
those of the central piece—the odontophors or the teeth. Between the 
oral angle and the angle of bifurcation at the free end differences may be 
observed in the spines, which in the latter are exactly like the adam- 
bulacral and different from the longer ones found at the angle of the 
mouth ; the brachial angle is formed by adambulacral pieces, which 
are very different from the large truncated teeth of the peristome ; 
and, lastly, the odontophor which is so characteristic a part of the 
disk, is altogether wanting at the angle of the brachial bifurcation. 
The author adduces photographs in support of these statements. 


Pourtalesia.*—Professor §. Lovén, the veteran author of the 
‘ Etudes sur les Echinoidées, has made another important contribu- 
tion to the morphology of the Echinoidea, based on a study of the 
characters of the remarkable deep-sea genus Pourtalesia, 

The first chapter deals with the general form of the skeleton, 
which, as in all Kchinids, is a hollow sac inclosing the visceral 
organs, and constituted by three distinct systems—ambulacral, peri- 
somatic or interradial, and calycinal or apical. The mode of numbering 
suggested in the ‘ Etudes’ is here again made use of. Whenever this 
skeleton has been accurately studied it has been found that its con- 
stituent elements are, in reality and fundamentally, arranged bilaterally 
and symmetrically on either side of the mesial plane, indicated by its 
antero-posterior axis. The archeonomous or old-fashioned type of 
the Clypeastride as well as the neonomous or new-fashioned Spatan- 
gide give distinct indications of the bilateral form of the adult. 
Though more difficult to detect, this bilaterality obtains also in the 
ancient Cidaride, and we have here “another instance of the validity 
of one of the laws more than once ascertained to underlie evolution, 
namely, that structures which are to be gradually but forcibly worked 
out during the course of geological ages into specialized and highly 
characteristic features, are virtually present within the fabric of the 


* K. Svenska Vet. Akad. Handl., xix. (1883) 95 pp. (21 pls.) (written in 
English). 


a2, SUMMARY OF CURRENT RESEARCHES RELATING TO 


earlier forms, though dormant, and, as it were, lying in abeyance, and 
to be detected only by a close scrutiny.” 

The general form of Pourtalesia is unlike that of any other known 
Echinid ; it has the form of an inverted short-necked bottle ; from the 
side the anterior line is seen to be bluntly truncated, while the dorsal 
surface is marked posteriorly, by a deep depression, behind which 
there is a truncated caudal prolongation. Anteriorly the test is 
suddenly bent inwards and backwards, so as to form a deep ovoidal 
recess leading to the mouth. It would seem as if “this anomalous 
configuration’ were due to “the dorsal portion of the body having 
moved forwards beyond the normal measure, and s0 as to leave behind 
the subanal part of the ventral portion, and as though its forepart 
produced into a rostrum projecting ventrally and compressed from 
both sides, had been drawn, by invagination, into the peritoneal 
cavity.” 

The perisomatic portion is next dealt with, and here perhaps we 
have the most anomalous condition of parts, for it is found that two of 
the interradii unite in the middle line and so form a continuous 
broad ring passing round the middle of the body; this arrangement 
appears also to be found in Spatagocystis, but it is only seen in 
P. jeffreysi and P. laguncula among the species of the genus Pourtalesia © 
as defined at present. Lovén makes the interesting remark that 
“once before, early in Mesozoic time, for a while and not unlike a 
trial soon given up, a structure resembling this was seen in the 
Collyritide, but imperfect, the ring being open ventrally and closed 
dorsally only.” As it obtains in P. jeffreysi, the author thinks that 
the radiate disposition of the skeletal elements is destroyed in an 
essential degree, “ and a tendency betrays itself towards an annular 
differentiation. of the bilaterally symmetrical constituents of the 
cylindroid skeleton.” 

The peristome likewise presents us with some very extraordinary 
characters; the structure of which leads us to think “ that what is 
going on here may be looked upon as the first move, so to speak, 
towards forming a rudimental mouth, a cavum oris, the invaginated 
parts of which, if they were flexible and provided with muscles, might 
be protruded like a proboscis.” Without here going into details we 
can only say that the author establishes his proposition that the joint 
participation of the ambulacra in the formation of the peristome, and 
the uninterrupted sequence of their plates does not obtain in the genus 
under consideration. 

The characteristic sensory organs (spheridia) first detected by 
Lovén in the region of the mouth of Echinids, are not, as in most, _ 
arranged in Pourtalesia in all the five ambulacra, but are absent from 
No. III., or that which is anterior and odd. In Pourtalesia, however, 
the ambulacrum in question is raised above the level of the peristome, 
so that we see that “of whatever nature the special changes in the 
surrounding water may be that their ciliated epithelium has to watch 
for, these changes seem to be of essential moment to the animal, solely 
when they take place in the vicinity of the mouth, or between the 
under surface and the ground on which the animal has to find its food.” 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. (533) 


The author next enters on an elaborate account of the structure 
of the pedicels of the Echinoidea, into the details of which our space 
prevents us following him. 

The next chapter deals with the important subject of the calycinal 
system, which he defines as consisting of a central ossicle, five costals, 
and five radials; he urges with much point the value of using these 
terms, and says truly that, when we know more “ the final terminology 
will come of itself.” The differences between the Crinoid and the 
Echinoid organization are sharply pointed out, and it is shown that 
in the latter the system “is rendered, to no small extent, a disputed 
ground, each of these (generative, water-vascular, anal) organs tend- 
ing to penetrate its substance and gain access to the surrounding 
water.” Tiarechinus, with its enormous calyx, appears to be the most 
antique of Echinoids. While a number of forms retain a stable 
relation of the parts we find that, when this is disturbed, the anal 
orifice is the first to alter its position; it is followed by the 
madreporite and generative pores, but the eyes remain stationary. 
The various stages of changes are traced in the most interesting and 
instructive manner, and the whole history thus philosophically 
summed up. “A large and powerful structure, closely specialized 
for a function of fundamental importance in the economy of 
some remote ancestral type, is inherited, in an early state, by a 
descendant in which, from a total change in the mode of life, the very 
purpose no longer exists for which it was originally contrived, and to 
which its parts were adapted. It long retains certain marked features 
which even to this day reveal its origin, but, unlike its crinoidean 
sister-structure which, with functions unaltered, multiplies its com- 
ponents—it remains simple as from the beginning, and, superfluous 
as it has become, gradually declines in intrinsic vigour, and is given 
up to subserving activities that had no share in its previous existence. 
Invaded by contending organs and yielding to their various ten- 
dencies it has its parts deeply modified and even to some degree 
suppressed, and, although still true to its type, and asserting, so to 
say, its unimpaired independence by redintegrating its injured frame, 
it dwindles, nevertheless, from age to age in every succeeding form, 
and is seen to fall into decay and dismemberment and to lose one by 
one its characteristics, till at last little remains of its original 
constitution. 

In trying to sum up the characters of the Pourtalesiadw the 
author feels the difficulty that the species which he has been able to 
study most completely, P. jeffreysi is of a more advanced character 
than the rest, but justly remarks that “this is not the first occasion, 
nor will be the last, when a species that chances to be the most 
familiar to us is put forward as the type of its kind.” The general 
form of the skeleton is subcylindroid, truncated anteriorly, tapering 
posteriorly ; there is a deep infrafrontal recess and a rudimentary 
buccal cavity. Bilateral symmetry is highly developed; the peri- 
somatic system predominates, while the calycinal is verging on decay. 
The breach of continuity in two of the ambulacra is without parallel 
among the members of the class. Like the Echinoneide they are 


754 SUMMARY OF CURRENT RESEARCHES RELATING TO 


alone among the neonomous Hchinoids in having homoiopodous 
pedicels, none of which are disciferous or converted into respiratory 
leaflets. The spines are Spatangean in characters. They do not 
attain to the level of the Spatangidz owing to the frequent loss of the 
organ of vision as well as by the simplicity of their pedicels. By 
some of their characters they point, though remotely, towards animals 
of another and higher type, animals of annulose differentiation. 
They are found in all oceans, and, on the average, at a depth of 
2900 metres. 

As to the origin of the deep-sea fauna Prof. Lovén utters these 
pregnant sentences: “ In the adult state most of the marine Evertebrates 
remain at their native station, wandering within its precincts. Their 
embryonic and larval age is their period of dispersal. Of numerous 
littoral forms, of different classes, tribes, and orders, currents must 
occasionally carry away the free-swimming larve ... . far into the 
sea, and during the course of succeeding generations early stages of 
many a species will in this way have reached the wide ocean. There 
they will have sunk, their development accomplished all through 
depths full of danger and more and more uncongenial, and a few of 
them will have settled on the bottom of the abyss, and fewer still will 
have come to thrive there. Among these some will long have their 
original character, and but slowly been modified, while others 
will have exhibited a latitude of variation unknown or rarely seen 
where they came from, but upon the whole there will be reasons for 
assuming the less altered forms to be new comers, the more deviating 
to be old inhabitants of the deep.” 


Anatomy of Larval Comatuie.*— Dr. P. Herbert Carpenter 
closely criticizes some of the results lately published by Perrier. 
He expresses his doubts as to the single curved water-tube of the 
“ cystid-phase”” opening to the exterior by a pore on the wall of the 
body, and inclines rather to Ludwig’s exact account of the primary 
water-tube as a dependence of the water-vascular ring opening into 
a section of the body-cavity, into which the primary water-pore, 
which pierces the oral plate, also opens. He doubts also the 

continuity of the pore and tube in later stages of the larva. 

“ The most startling statement” on the part of Perrier is that the 
plexiform gland of Crinoids corresponds, not with the ovoid gland of 
Star-fishes and Urchins, but with the stone-canal of these echinoderms. 
The ground for this statement can hardly be histological, and it is 
difficult to imagine what it may be. The relations of the axial organ 
to the cirri can hardly be seriously maintained, unless Perrier will 
show that the cirrus-vessels are radial and derived from the cavities 
of the chambered. organ. Dr. Carpenter reiterates the expression of 
his hope that Perrier will publish more complete accounts and 
illustrate them by a number of figures. 


* Quart. Jaune Micr. Sci., xxiv. (1884) pp. 319-27. 
+ See this Journal, ante, p. 389. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ios 


Ccelenterata. 


Notes on Meduse.*—C. Keller has some observations on Coty 
lorhiza tuberculata, which appears at certain periods in the Mediter- 
ranean, and the habits of which invite the question, what are the 
causes of its regular migration, and whence does it come? From 
the series of observations which the author was able to make he 
was led to conclude that it is highly probable that this Medusa is 
a true deep-sea form, which only comes to the surface for a time, and 
spends most of its life in its sessile condition on the floor of the sea. 
The cause of the migration appears to be associated with reproduc- 
tion, the nurses being littoral, the young Meduse deep-sea forms, 
so that the sexualiy mature animal rises to the surface and lives 
pelagically. With reference to the theories that may be based upon 
these facts Keller quotes Carl Vogt, who has lately expressed his 
belief that the class Hydromeduse has arisen from two different 
stocks, one of which has produced the Acraspedota and the Scypho- 
stomata, the other the Craspedota, Siphonophora, and hydroid polyps, 
and who, further, has expressed his belief that fixed and parasitic 
creatures are always produced by special adaptation from forms that 
were primitively free. Though this, of course, is not true of Comatula, 
yet we must remember how infinite are the powers of adaptation, and 
not summarily reject it as not applicable to the Medusz. 

The yellow cells of C. tuberculata are next discussed, and the 
author declares his agreement with the views of Geddes and of 
Brandt that the bodies are algar in nature, and thinks that the 
symbiosis is explicable on the supposition that the cells in question 
are found only in the pelagic generative forms, which demand a 
larger supply of oxygen. 

A new Medusa—Orchistoma agaraciforme—the first species of the 
genus found in Europe (Mediterranean), is next described. As the 
development of the Orchistomide is as yet altogether unknown, it is 
interesting to learn that Keller has found some young specimens; it 
_was found that the gonads are only apparently canular, and that they 
really arise from a gastric outgrowth, a condition as yet unique 
among the Thaumantide or Leptomeduse. There appears to be a 
considerable amount of metamorphosis ; the most important changes 
obtaining in the radial canals, which increase in number; in the 
gastric cavity, which diminishes in size; and in the proportionately 
late development of the large gastric stalk. 


Revision of the Madreporaria.j—Prof. P. M. Duncan gives a 
revision of the families and genera of the Sclerodermic Zoantharia, 
Ed. & H. or Madreporaria (M. Rugosa excepted). Since Milne- 
Edwards and Haimes’ work of 1860, no systematic revision of the 
Madreporaria has appeared, while since then a great number of new 
genera have been founded; hence the necessity for a revision has 
arisen, and more especially in consequence of the morphological 
researches of Dana, Agassiz, Verrill, Lacaze-Duthiers, and Moseley. 


* Recueil Zool. Suisse, i. (1884) pp. 403-22 (1 pl.). 
+ Journ. Linn. Soe, Lond. (Zool.), xviii. (1884) pp. 1-204. 


756 SUMMARY OF CURRENT RESEARCHES RELATING TO 


In the present revision the sections Aporosa and Perforata remain, 
but shorn of some genera; the old family Fungide becomes a section 
with three families, two of which are transitional between the sections 
just mentioned. The section Tabulata disappears, some genera being 
placed in the Aporosa, and the others are relegated to the Hydrozoa. 
The Tubulosa cease to be Madreporarian. Hence the sections treated 
are Madreporaria Aporosa, M. Fungida, and M. Perforata. The 
nature of the hard and soft parts cf these forms is considered in 
relation to classification, and an appeal is made to naturalists to 
agree to the abolition of many genera, the author having sacrificed 
many of his own founding. The criticism of 467 genera permits 336 
to remain, and as a moderate number (36) of sub-genera are allowed 
to continue, the diminution is altogether about 100. The genera are 
grouped in alliances, the numbers in families being unequal. Sim- 
plicity is aimed at, and old artificial divisions dispensed with. There 
is a great destruction of genera amongst the simple forms of Aporosa, 
and a most important addition to the Fungida. The genera Stder- 
astree and Thamnastre are types of the family Plesiofungida, as are 
Microsolenia and Cyclolites of the family Plesioporitide. The families 
Fungide and Lophoseride add many genera to the great section 
Fungide. There is not much alteration in respect of the Madre- 
poraria Perforata, but the sub-family Eupsammine are promoted to a 
family position as the Hupsammide. 

Prof. Duncan also describes * a new genus of recent Fungida, 
Family Fungine Hd. and H., allied to the genus Micrabacia, and 
which he names Diafungia. There is one species, D. granulata. 


Porifera. 


New Gastreades from the Deep Sea.j—Prof. E. Hiackel has 
found among the collections of the ‘ Challenger’ organisms which 
agree in the following characters; they live at the bottom of the sea 
(in rare cases littorally, in the majority at great depths) and have a 
firm skeleton formed of the substance there found, which they unite 
into a solid cement by means of a small quantity of organic cementing 
matter ; some of these skeletons formed quite a museum of Radiolaria, 
consisting as they did of the most delicate shells of several hundred 
species. The skeletons are either external or internal; the former 
being due to the secretion of mucus from their outer surface, while 
in the latter the foreign bodies were taken into the ectodermal cells. 
In the former the secretion contains no cell-nuclei, in the latter they 
consist distinctly of protoplasm, in which a few, or in rare cases, 
a number of nuclei were to be found; we have then here to do with a 
more or less modified syncytium. The organisms vary much in 
form and size, the smallest being from 1-3 mm. in diameter, the 
largest from 80-120. The organisms that form the cemented skeleton 
may be either Protozoa or Metazoa; the former are, in a few cases, 
colossal Lobose, allied to Difflugia; in many cases they are true 
Rhizopoda, and the majority Thalamophora. 

* Journ. Linn. Soc. Lond. (Zool.), xvii. (1884) pp. 417-9 (1 pl.). 
+ SB. Jenaisch. Gesell. f. Med. u. Naturwiss., 1883 (1884) pp. 84-9. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. fiw 


The cemental Gastreades fall into two groups, which have the 
same relation to one another as have the Ascones to the Leucones 
among the Calcispongiz. In the simple and phylogenetically older 
forms, the wall of the gastric tube is thin and solid, but in the 
further developed it is thicker and traversed by gastric canals. The 
former, allied to the already described Haliphysema and Gastrophysema, 
are either branched (Dendrophysema) or plexiform (Clathrophysema). 
The latter belong to a new group called the Cementaria ; resembling 
many Dysidiide, they are distinguished by the complete absence of 
ectodermal pores, so that the water only enters the irregular canal- 
system (the spaces of which are completely or partly invested by 
endodermal flagellate epithelium) by the mouth-orifices. In the 
endoderm there are scattered ovarian cells. Ccmentascus forms 
simple tubes, with a single oral orifice ; Caementoncus has several 
orifices and is irregular in form ; Cementissa forms flat lobate crusts ; 
Cementura branched creeping or dendriform masses with several 
mouth-openings. Hiackel thinks that the Orthonectida are allied to 
the Cyemaria, and that the Trichoplax of F. E. Schultze is a perma- 
nent Discogastrula form. 


Siliceous Spicules of Sponges.*—J. Thoulet has examined the 
structure and other characters of the spicules of various sponges 
collected during the last cruise of the ‘Talisman. They were 
separated by treating the sponge with hydrochloric acid. The 
acicular spicules lost 13-18 per cent. of weight on heating to red- 
ness for ten minutes in a platinum crucible. Before the blow- 
pipe they were whitened, or became slightly ochreous in colour, 
without a trace of fusion. Stellate spicules of five rays lost 12-86 per 
cent. on calcination. The specific gravity, obtained by flotation in a 
solution of iodides, was 2°032. But the spicules have a delicate tube 
along the centre generally less than ‘001 mm. in diameter; and 
allowing for this, the author obtained by calculation, 2-0361 as the 
true specific gravity—which is that of opal. 

The spicules are easily attacked by different chemical agents, so 
that they ought to be very readily dissolved in sea-water on the death 
of the animal. They were analysed after. calcination by Boricky’s 
process, by means of pure hydrofluoric acid, after first boiling in 
nitric acid and calcining, and they were proved to be pure silica. 
When not previously calcined, but simply washed, the process yielded 
a residue of hydrofluosilicate of soda in hexagonal prismatic crystals, 
the origin of which it is hard to explain unless it be that the minute 
tube of the spicules contains sea-water. 


Fresh-water Sponges and the Pollution of River-water.{—E. 
Potts has examined the sponges found in the forebay of the Phila- 
delphia waterworks when the water was withdrawn, and considers 
that the sarcode of fresh-water sponges does not slough off at the 
approach of winter, so that these organisms do not ordinarily pollute 

* Bull. Soc. Mineral. France, April 1884. Cf. Amer. Journ. Sci., xxviii. 


(1884) p. 76. 
t Proc. Acad. Nat. Sci, Philad., 1884, pp. 28-80. 


758 SUMMARY OF CURRENT RESEARCHES RELATING TO 


the water unless torn to pieces by violent freshets. He believes that 
the whole of the sarcode retires into the statoblasts, from which it 
issues again in spring. 


Protozoa. 


New Infusoria.—Dr. A. C. Stokes describes * a new genus and 
six new species of fresh-water Infusoria. 

Hymenostoma n. gen., H. hymenophora resembling Lembadion. 
Trachelophyllum vestitum with needle-shaped objects scattered through- 
out its substance which may be trichocysts, but their form and the 
action of the light suggest that they may be crystals. They closely 
resemble the acicular raphides of Lemna and other plants. T. tachy- 
blastum, the specific name of which (“sprouting quickly”) was 
suggested by the rapidity with which the animal repaired an injury 
it sustained by a collision with an Oxytricha. Litonotus pleurosigma 
resembling L. fasciola but differing from it and all other species of 
the genus in the multiple contractile vesicles. LL. helus and Petalo- 
monas disomata. 

A new species of Vorticella (V. Lockwoodit) is also described + by 
the same writer. The characteristics by which it may be dis- 
tinguished from all Vorticelle are the existence and structure of the 
cuticular prominences and the undoubted presence of two contractile 
vesicles. 

J. P. McMurrich describes { Metopus striatus which he considers 
to be sufficiently distinguishable from the other species (M. sigmoides) 
to justify its being treated as a distinct species. 

J. G. Grenfell records § four new Infusoria from Bristol; Zootham- 
nium Kentii differing from Z. dichotomum and all other species of the 
genus in the characteristic covering of flocculent matter; Pyxicola 
annulata || very like P. Carteri, but differing in dimensions and 
undulations ; Platycola bicolor, so named ‘from the two colours of 
the lorica” (lorica dark yellow, with a colourless neck)—it has a 
very delicate membranous hood which has a large oval opening, is 
retractile, and projects backwards from the top of the ciliary disk 
covering the opening; P. aurita (n. sp. ?). 

C. L. Herrick describes { Ophridium problematicum and an infu- 
sorian closely related to Paramecium, but differing in several inter- 
esting particulars from it and its allies. In form this animal is _ 
linear lanceolate (about 0:2 mm. long), tapering posteriorly to an 
almost acuminate point. Anteriorly is a long vibratile proboscis, or 
flagellum, which exceeds, when extended, the whole length of the 
body. The mouth is situated at the base of this proboscis, and opens 
into a very short infundibulum. The whole surface of the body and 
proboscis is covered with minute cilia, which are inserted in rows, 


* Amer. Mon. Mier. Journ., v. (1884) pp. 121-5 (9 figs.). 
+ Amer. Natural., xviii. (1884) pp. 829-30 (2 figs.). 

{ Ibid., pp. 830-2 (1 fig.). 

§ Journ. of Micr., ili. (1884) pp. 133-8 (1 pl.). 

|| But see Dr. Leidy, this Journal, iii. (1883) p. 77. 

4 Science, iv. (1884) p. 73. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 759 


giving the body a punctate appearance. Longer cilia surround the 
mouth. The sarcode is transparent, and, apart from a few greenish 
food-balls, contained only a large number (over a dozen) of oval 
bodies of a similar character (endoplastules in an unobserved coiled 
endoplast?). The motions of the animal are very quick, and are 
occasioned chiefly by the whip-like motions of the proboscis, which 
is extremely vigorous in movement, and alters its form greatly. 
Apart from this rapid motion, it can propel itself slowly by means 
of the cilia covering the entire surface. It is the type of a new 
genus, and is named Phragelliorhynchus nasutus. 


Parasitic Peridinian.*—G. Pouchet has met with a Peridinian 
which in its early stage is parasitic on Appendicularie, These 
parasites are pear-shaped, about 170 to 180 w long, with a nucleus 
large in proportion. In colour they are a deep brown; they are 
enveloped in a thin cuticle which they keep on becoming free, whilst 
they abandon their pedicel. These detached individuals float in great 
abundance on the surface of the sea and there undergo free or 
independent segmentation, subdividing after the manner of a fecundated 
vitellus into uninucleated spheres dwindling in size and growing 
paler in colour as the process continues; but the products of this 
segmentation always remain independent. A very thin cuticle is 
thrown off as they divide. The spheres finally resulting, measuring 
no more than 10-13 p, develope a long flagellum and a crown ef cilia, 
and become minute Peridinians allied to Pulvisculus of Ehrenberg 
Gymnodinium pulvisculus of Bergh). The whole process occupies 
about 24 hours. 


Observations on Flagellata.j—F. Blochmann commences with 
some notes on Trichomonas vaginalis, at the anterior end of which 
there are three flagella, from the base of which an undulating mem- 
brane extends to about the middle of the body ; this membrane, never 
hitherto observed, may be best seen if the creature is allowed to die 
gradually. The T. batrachorum of Perty (the Cimenomonas batrachorum 
of Grassi) is next considered, and here also an undulating membrane 
was detected. If the monad is allowed to remain for some time under 
the pressure of the cover-glass the whole margin of the animal is 
seen to exhibit an active undulatory movement, though, of course, 
this is not so regular as that of the membrane. A similar phenomenon 
is to be observed in Trichomastix lacerte, a species lately detected by 
Biitschli in the cloaca of Lacerta agilis; it has four flagella, one of 
which is half as long again as the animal and is directed backwards. 
Ozyrrhis marina is the last form described; within their bodies a 
large number of fat-drops, often of considerable size, are to be 
detected ; they take in solid nutriment. The author was able to 
observe their multiplication by a mode of transverse division. 

Geometry of Radiolaria.t—Prof. E. Hickel points out that the 
four orders of the Radiolaria are distinguished by their geometric 

* Comptes Rendus, xeviii. (1884) pp. 1345-6. 


+ Zeitschr. f. Wiss. Zool., xl. (1884) pp. 42-9 (1 pl.). 
t SB. Jenaisch. Gesell. f. Med, u. Naturwiss., 1883 (1884) pp. 104-8. 


760 SUMMARY OF CURRENT RESEARCHES RELATING TO 


form; in the Acantharia we have the quadrate octohedron, where 
twenty radial spines are arranged in five sets of four spines each, 
which are set quite regularly in meridional planes. In the Nassellaria 
or Monopylee there is at first a monaxial form, which is in many 
cases rendered bilaterally symmetrical; this is true also of the 
Pheedoria or Tripylee. Stereoscopic forms are seen in the Spumel- 
laria. 

The Spheroida, which may be regarded as the stem-form of all 
Radiolaria, ordinarily retain the spherical form of the central capsule, 
and frequently give rise to the endospheric polyhedron; from these, 
more complex forms arise by the development of spines along certain 
rays. The Prunoidea are at first monaxial ellipsoids, and they finally 
produce the much more complex Zygartide. The Discoidea arise 
from the Spheroida by the shortening of the vertical primary axis, 
and they at first have the form of biconvex lenses. The Larcoidea 
begin with simple ellipsoid shells, and become complicated by the 
development of further systems of network. 


Polythalamian from a Saline Pond.*—E. v. Daday describes 
a new genus—Hnizia—of Polythalamians from saline waters, which 
have been studied by Prof. Entz, who finds that the infusoria living 
therein are new forms, or have as yet been found in the sea only, or 
are common to both fresh and sea water, while a fourth of the whole 
number are only ‘known as fresh-water forms. The new genus is 
characterized by having a multicamerate imperforate shell, which 
contains a large number of siliceous plates ; the chambers are coiled 
from left to right, and are only completely visible from the convex 
side; at the outer partition of the terminal chamber there are larger 
orifices, which are oval and tubular, and two smaller which are, vircular. 
Tetrastomella is proposed as the specific name. Pa“ 

In the form of its shell Entzia resembles Rotalia, and belongs 
to the group of the Helicostegia; the largest of the 16-chambered 
individuals measured 0°42 mm., while the smallest 6-chambered 
shell measured only 0°08 mm. As in Rotalia, the partitions 
between the chambers were formed of two lamellw, one belonging 
to the chamber in front and the other to that behind, but there 
is not here any interseptal space; in all, as in the last partition, 
there are two large and two smaller holes. As the siliceous 
plates are completely imbedded in the substance of the shell, 
the surface of the latter is, notwithstanding their presence, quite 
smooth; they cannot, therefore, be regarded as foreign bodies, but 
must be supposed to have been formed by the protoplasm. On the 
whole, an investigation into the characters of the shell shows that it 
unites peculiarities which are separately characteristic of chitinous 
and arenaceous Rhizopods, and the close allies of the form are to be 
found not so much in Rotalia, which it resembles in appearance, as 
in Difflugia and the arenaceous Mono-and Polythalamia. The author 
sums up his views as to the systematic position of Knizia in the 


* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 465-80 (1 pl.). Cf. Gruber’s note, 
this Journal, ante, p. 580, which should have followed the above. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 761 


following terms: It is the only as yet known continental Poly- 
thalamian, and in the form of its shell resembles that of the sub-family 
Rotaline of the group Globigerinz ; in structure the shell resembles 
that of Trochammina ; in the structure of its partitions it agrees with 
the perforate Polythalamia’; in that of the orifices of these partitions 
with the Lagenide; the chemical constitution is that of Diflugia, 
Trochammina, and some of the Globigerina, and it closely con- 
nects the last with the Lagenidew by means of Trochammina and the 
Rotaline. 


Nuclear Division in Actinospherium eichhornii.*—R. Hertwig 
concludes from his observations on the resting nucleus that the 
coloured constituents of the nucleus (chromatin or nuclein) are not 
spongy bodies; all the nuclein is contained in nucleoli, which are 
stained by reagents. A subject of greater difficulty is presented by 
the parts which are formed in addition to the nucleoli within the 
nucleus. These are (1) the granulation which becomes visible on 
the addition of reagents; (2) the paranuclear pieces which in the 
fresh condition are seen to have various forms; (3) the highly 
refractive corpuscles; and (4) the nuclear membrane. The first 
three appear to be referable to a common structure of colourless 
substance, which may be called paranuclein or achromatin, and 
which fills up the interspaces between the nucleolus and the nuclear 
membrane, It may be regarded as due to special thickenings of the 
achromatic network. The author is acquainted with essentially 
similar phenomena, which have presented themselves in the nuclei 
of insects, and of which he will give an account at a later period. 

The mode of division of the nucleus, as seen in Actinospherium, is 
intermediate in character between what is seen in plants and animals 
on the one hand, and in Protozoa on the other; in the latter, which 
approach most nearly the diagrammatic scheme, the biscuit-shaped 
constriction of the nucleus is most apparent; internal differentiations 
of the nuclear substance are either completely wanting, or are nearly 
fibrillar. (An exception to this is seen in the paranuclei of the 
Infusoria.) On the other hand, in plants and animals the biscuit- 
shaped constriction is obscure, the limits of the nuclear substance 
and protoplasm disappear, and there is a mixture of the two sub- 
stances. The whole division of the nucleus appears, therefore, as a 
complicated and extremely regular rearrangement of the nuclear 
particles, which lead to the important differentiation of achromatic 
nuclear filaments and of chromatic elements; the two substances are 
so sharply separated that they might be taken for elements which 
had nothing to do with one another. 

In Actinospherium we have, as in the other Protozoa, those changes 
in form which the whole nucleus undergoes during division; but as 
to its internal structure there are many points in which the nucleus 
resembles that of animal ova; anuclear plate is formed, which divides 
into lateral plates that separate from one another and the parts of the 
lateral plates give rise to achromatic filaments. Before the appear- 


* Jenaisch. Zeitschr, f. Naturwiss., xvii. (1884) pp. 490-517 (2 pls.). 
Ser, 2.—Vo. IV, 38 5 


762 SUMMARY OF CURRENT RESEARCHES RELATING TO 


ance of the nuclear plate there is a stage in which it resembles that of 
the Infusoria; as in them, bands, which may be coloured for their 
whole extent, reach from pole to pole. This would seem to show that 
in Actinospherium the achromatic filaments contain particles of 
chromatin throughout their whole extent, and the same is probably 
true of the Infusoria. 

Tn addition to the interest which surrounds the nucleus of Actino- 
spherium in consequence of its intermediate position, the mode of 
formation of the lateral plates is also of interest. The view of 
Flemming that in animal cells these plates are primitively laid down 
separately does not apply to Actinospherium, where the first rudiment 
of the nuclear plate is a single row of granules. The nucleus is also 
distinguished by the possession of polar plates, or aggregations of homo- 
geneous substance which are interpolated between the striated part 
of the nucleus and the homogeneous protoplasmic cones ; they appear 
to be derivatives of the cell-nucleus, formed by the clearing up of 
its peripheral parts. The nuclear filaments are distinguished from - 
those of animal and vegetable cells by their finely granular condition ; 
they appear to consist of paranuclein, together with minute remnants 
of colourable nuclein. 


Parasite of the Wall of the Intestine of the Horse.*—M. Flesch 
gives an account of a parasite which he has proposed to call Globidiwm 
leuckarti, and which was found particularly in the connective tissue of 
the intestinal villi of the horse, where its presence may give rise to 
subacute inflammation. It ordinarily has.a spherical or ellipsoid 
body sharply marked off by its capsule; in most cases its wall is 
hollowed by a special fusiform or semilunar cavity, which is com- 
pletely filled by a granular body or, as the author calls it, the 
accessory body. In position it resembles the remains of the yolk in 
the ova of Tenia. In another form the refractive spherules in the 
interior of the parasite were solely parietal in position, and the 
central space was occupied by a protoplasmic mass, which was very 
uniformly granular. The author describes the stages in development 
that he was able to observe, and then addresses himself to the question 
as to whether he had here to do with a phase in the alternation of 
generations of a higher organism, or whether the parasite was a 
Sporozoon. He next gives a list of the known parasites of the horse, 
which, as being fuller than that of Linstow, may be of use for other 
purposes, and discusses the probabilities of his new form being a stage 
in the life-history of any one of these ; this view being rejected he 
addresses himself to the Sporozoon-view, against which it seems there 
is nothing to be said, but in favour of which there is almost as little; 
in fact it is, at present, impossible to assign a definite position to the 
parasite. The relatively large capsules, and their position in the con- 
nective tissue are against its being a Sporozoon; the part played by 
the accessory body is unknown, and the evidence as to its being ex- 
pelled from the organism is incomplete. The author hopes to be able to 
make further and more complete investigations and meanwhile proposes 


* Recueil Zool. Suisse, i. (1884) pp. 459-89 (1 pl.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 763 


to speak of this obscure and abnormal parasite by the name he 
originally suggested of Globidiwm leuckarti. 


Sutherlandshire ‘‘ Eozoon.’’*—Prof. M. F. Heddle, after a careful 
examination of the Eozoon-like structure that occurs in the marbles of 
Assynt, recalls his previously expressed opinion as to its non-mineral 
character and attributes to it a purely inorganic origin. The greater 
part of this structure is formed of dark serpentine with some mag- 
netite, whilst in the calcareous layers are imbedded fibres apparently 
of wollastonite. Prof. Heddle states in a footnote that having un- 
ravelled the Scottish Eozoon, he entered upon an inquiry into the 
Canadian, in which he finds nothing he did not see in the Scotch 
Specimens; at the same time the specimens examined were possibly 
not good examples. 


BOTANY. 


A. GENERAL, including Embryology and Histology of the 
Phanerogaimia. 


Continuity of Protoplasm.}—P. Terletzki has investigated this 
question with a view of determining what organs and what tissues in 
the same plant display the phenomenon. For this purpose he has 
taken in the first place Pteris aquilina, and has found a distinct 
protoplasmic connection, in the rhizome, between the parenchymatous 
cells, the conducting cells, and the sieve-cells, in each case among 
one another, and between the sieve-cells and the conducting cells. | 
On the other hand, he could detect no connection in the following 
cases :—between the cortical cells among one another, between the 
cortical and parenchymatous cells, the cells of the supporting bundles 
among one another, the supporting bundles and the parenchyma, the 
cells of the protecting sheath among one another, the protecting 
sheath and the parenchyma, the protecting sheath and the conducting 
cells, the bast-cells among one another, the bast-cells and the con- 
ducting cells, the bast-cells and the sieve-cells, the conducting cells 
and the scalariform vessels, the conducting cells and the tracheids 
(annular or spiral conducting cells). These remarks apply to the 
mature condition of the plant, and it is possible that in the cambial 
condition the protoplasm of the whole of the cells may be in 
connection. 

The general facts were the same in other organs of P. aquilina, 
and in other ferns. 

Protoplasm was found in the intercellular spaces, especially in 
the parenchyma of the rhizome, also in the parenchyma of the leaf- 
stalk ; and this intercellular protoplasm was in connection with the 
cellular protoplasm. 


* Mineral. Mag., v. (1884) pp. 271-324 (11 figs.). 
+ Ber. Deutsch. Bot. Gesell, ii. (1884) pp. 169-71. 


3 Er 2 


764 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Continuity of Protoplasm.*—G. Schaarschmidt believes that all 
vegetable cells inclosed in a cell-wall and combined into a tissue 
are placed in uninterrupted connection by means of threads of 
protoplasm. aus 

With regard to the occurrence of protoplasm in intercellular 
spaces, he finds intercellular masses of protoplasm in Liriodendron 
tulipiferum, also in the bud-scales of Aisculus Hippocastanum, in 
Solanum Pseudocapsicum, Viscum album, &c. They occur especially 
where the cells themselves contain no great quantity of protoplasm, 
and can convert themselves into true cells by becoming invested with 
a cell-wall; secondary intercellular spaces are then formed between 
these and the older cells. This intercellular protoplasm the author 
believes to be derived from the threads which pass from cell to cell. 


Osmotic Power of Living Protoplasm.;—By an ingeniously 
contrived apparatus M. Westermaier claims to have proved that the 
pressure of the parenchymatous cells of the root-system, and the 
osmotic suction of the protoplasm in the parenchyma of the stem, 
acting together, are capable of raising a column of water to any given 
height from the soil. 


Structure of Pollen-grains.t—J. Vesque points out that the 
pores in the pollen-grains are so arranged that, no matter in what 
position the grains fall on the stigma, one at least of the pores is 
ordinarily in contact with the moist membrane of the stigmatic 

apille. The larger the grain the greater the number of pores (or 
of folds), and their number, therefore, cannot be considered of great 
taxonomic value. M. Vesque has found pollen-grains of Hieracium 
having three to four pores, and that in the same anther. 

The disposition of the external ornamentation of the pollen-grain 
does not appear to depend on its mode of development, but on a 
fixed geometrical law—that of phyllotaxy. Thus the complex pollen- 
grain of the Chicoracesw, were it completely spherical, would be a 
pentagonal dodecahedron; but as it is slightly ellipsoid, hexagonal 
network is combined with the pentagonal. In the simplest case, that 
which obtains in Scolymus, three hexagonal faces furnished with pores 
are seen on the equator of the grain, the twelve remaining faces being 
pentagonal, It is evident that the number of hexagonal faces in- 
creases the more the grain approaches the cylindrical form. Thus 
in Sonchus, Helminthia, and Lactuca it has twenty-one faces, three 
hexagonal ones with pores, six without, and twelve pentagonal ones. 


Seeds of Abrus precatorius.§—W. Tichomiroff classifies the 
seeds of Papilionaceze hitherto examined into three classes, according 
to the nature of their reserve material, viz.:—(1) Seeds containing a 
fatty oil, starch, glucose, and aleurone, such as Arachis hypogea and 
Dipteria odorata ; (2) those containing starch and aleurone only, as 


paaee!: Noy. Lapok, viii. (1884) pp. 17-20. See Bot. Centralbl., xviii. (1884) 
p. 162. 

+ Ber. Deutsch. Bot. Gesell., i. (1883) pp. 371-83. 

{ Comptes Rendus, xevi. (1883) pp. 1684-6. 

§ SB. Vers. Russ. Naturf. u. Aerzte, Aug. 25, 1883. See Bot. Centralbl., 
XViii. (1884) p. 189. 


ZOOLOGY AND BOTANY, MIOROSCOPY, ETO. 765 


Pisum sativum, Phaseolus multiflorus, and Physostigma venenosum ; 
(3) those containing coarsely granular aleurone and a fatty oil, as 
Inpinus mutabilis and Trigonella Fonum grecum. Those of Abrus 
precatorius constitute a distinct type; they contain a fatty oil and 
albuminoids in the form of finely granular protoplasm, but neither 
aleurone nor starch. Another characteristic is the persistence of the 
nucleus and nucleoli in the peripheral parenchymatous layers of the 
cotyledons. The crystals sometimes found in the parenchymatous 
cells destitute of nucleus may consist of stearic acid or hesperidin. 
The cell-wall is thickened in a porous manner, is not doubly refrac- 
tive, and consists of pure cellulose. The testa is composed of four 
layers, viz. :—(1) rods, colourless in the red part of the seed, while 
in the black spot they are of a purple-violet colour; (2) palisade- 
cells, distinguished by their length, their branching, and by the 
folding and small diameter of their lower end; (3) parenchyma, com- 
posed of cells elongated in the tangential direction ; (4) albumen, the 
cellular nature of which is clearly defined in the first layers, while 
the cells at a greater distance lose their individuality by becoming 
flattened radially, and at length coalesce into a homogeneous pellicle, 
which cannot be decomposed into its separate cells even by macera- 
tion in chromic acid. In caustic potash this pellicle swells up 
- strongly, and forms local projections. The hilum has two of the 
layers of rods, but no palisade-cells, these being replaced by scleren- 
chyma. With the exception of the albuminous layers the cell-walls 
display distinct cellulose-reaction. By chloride of iron the presence 
of tannins can be recognized in the albuminous layers and rods. 


Comparative Anatomy of Cotyledons and Endosperm.*—J. God- 
frin states, as a general result of a comparison of the structure of the 
embryo and the endosperm, that those embryos the cotyledons of 
which contain starch, whether alone or together with aleurone, are 
never accompanied by endosperm. Those, however, which contain no 
aleurone, even when thick (as Amygdalus, Armeniaca, Prunus, Corylus, 
Juglans, Carya, &c.), may contain an endosperm, which is however 
always very small. Embryos with thin or foliaceous cotyledons, are 
not necessarily accompanied by endosperm, as witness Hedysarum 
sibiricum, Casuarina quadrivalvis, Grevillea robusta, Hakea saligna, and 
Acer. 

The author classifies cotyledons under two heads: thick or tuber- 
cular, and thin or foliaceous. The former, when mature, have a 
simple epidermis without stomata or hairs, and in the interior a thick 
parenchyma with large globular cells, between which are a number of 
air-cavities. On germination very little modification of the tissues 
takes place. Foliaceous cotyledons have, when mature, a simple 
epidermis, often provided with stomata more or less developed; the 
parenchyma is much smaller in mass, but is always divided into two 
distinct layers. They vary greatly in their mode of development 
during germination. In those which contain aleurone its absorption 
is the first indication of germination. 


* Bull. Soc. Bot, France, xxxi. (1884) pp. 44-51. 


766 SUMMARY OF OURRENT RESEAROHES RELATING TO 


Underground Germination of Isopyrum thalictroides.*—This 
species presents one of the few examples of underground germination 
among flowering plants. A. Winkler has examined the process in its 
various stages, and points out that it exhibits a difference from the 
similar phenomenon in Anemone nemorosa and ranunculoides belong- 
ing to the same natural order. While in Anemone the unstalked 
cotyledons project from the testa of the seed, and, as in typical 
dicotyledons germinating above the surface of the soil, are opposite to 
cne another, in Isopyrum they remain inclosed within the testa, and 
are placed on tolerably long stalks. 


Stomata of Pandanacee.t{—R. F. Solla has closely studied the 
stomata in the leaves of a large number of species of Pandanus, and 
distinguishes three types:—(1) the simplest and most common form, 
represented by Pandanus tnermis, in which the cells contributing to 
its formation are only two in number; (2) the type of P. graminifolius, 
which occurs only in a few Pandanacee ; the auxiliary cells, eight in 
number, are all thickened, their apices thus forming a protuberance 
which rises above the level of the epidermal cells, the walls of the 
latter being also thickened; (8) the type of P. utilis, resembling the 
stomata of Aloe and other allied plants ; the thickening here extends 
from the auxiliary cells to the epidermal cells to such an extent as to 
form little lumps on the surface, completely concealing the outline 
of the stoma. A number of measurements are given of the size of 
the stomata in different species, and of the relative number found on 
a unit of superficies. 


Changes in the Gland-cells of Dionea muscipula during 
Secretion.j—According to W. Gardiner there are four periods in the 
process of digestion by the leaves of the Venus’s fly-trap, viz. the 
resting, the secreting, the absorbing, and the period of recovery. 

In the resting stage the gland-cells exhibit the following structure : 
—In each cell the protoplasm is closely applied to the cell-wall, 
leaving a large central vacuole, which is filled with the usual pink 
cell-sap. The protoplasm is very granular, especially round the 
nucleus, which is situated at the base of the cell, and is large and 
well defined. At the end of the secreting period, which appears to 
be about twenty-four hours after stimulation, movements of the pro- 
toplasm have taken place, in consequence of which the nucleus now 
occupies the centre of the cell; numerous strands of protoplasm 
radiate from the nucleus to the parietal protoplasm, dividing the 
vacuole into several smaller ones. The protoplasm is now nearly 
homogeneous, clear and hyaline, and the nucleus has become much 
smaller. In the ordinary leaf-tissue special cell-contents make their 
appearance after the absorption of the food. About thirty-six hours 
after feeding the cells contain a large number of tufts of crystals in 
the vacuole, which adhere to the inner surface of the protoplasm. 
They consist of fine acicular crystals, which crystallize out with 
great regularity, and radiate from a central point. They are of a 

* Flora, Ixvii. (1884) pp. 195-8 (1 pl.). 
+ Nuov. Giorn. Bot. Ital., xvi. (1884) pp. 171-82 (2 pls.). 
{ Proc. Roy. Soc., xxxvi. (1884) pp. 180-1. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 767 


yellow-green colour, insoluble in alcohol, in 1 per cent. acetic acid, 
and in 1 per cent. hydrochloric acid, soluble with difficulty in 5 per 
cent. solution of potash. After forty-eight hours the cell-contents 
are of a different nature. The cells now contain numerous bodies 
which present the appearance of flat spherocrystals. They are 
usually perfectly circular in outline, and are clear and colourless, 
insoluble in alcohol, but extremely soluble in water. 
In Drosera similar changes take place, but much more rapidly. 


Septal Glands of Monocotyledons.*—P. Grassmann describes the 
nectar-glands found in the septa of the ovary, which are peculiar to 
Monocotyledons, and in them occur only in the series of Liliiflore 
and Scitamines. They occur one in each septum, and therefore 
almost invariably three in each ovary. The gland forms in the 
septum a fissure of varying size and form, visible even to the naked 
eye. It usually occupies the greater part of the septum, and is bounded 
on each side by a secreting layer, consisting of from two to three rows 
of cells. In the same family they are very constant in form and 
size. The glands are filled with nectar, which escapes by means of a 
narrow canal to the receptacle, the mode of escape varying according 
as the ovary is superior, half-inferior, or inferior. 

The glands are formed by the incomplete cohesion of the carpels 
in the septa; they are recognizable at a very early stage of develop- 
ment, and are then quite destitute of nectar, and the stages of cohesion 
can be very readily followed. Their object is unquestionably the 
attraction of insects to assist in fertilization. They are found only in 
species with conspicuous flowers; the nectar always contains grape 
sugar, and, when it flows out of the glands, either collects on the 
receptacle or unites with the juice flowing from nectaries in other 
parts of the flower. It begins with the opening of the flower, and 
usually lasts several days. ‘The canal is also surrounded by secreting 
cells which pour out nectar. 


Secretory System of Composite.t—According to P. Van Tieghem, 
the secretory system of Composite presents itself in three different 
forms—as oleiferous canals, as anastomosing laticiferous cells, and as 
long, isolated resiniferous cells. Disregarding some transitional 
forms, the first of these types is characteristic of the Radiiflore, the 
second of the Liguliflore, and the first and third of the Tubuliflore. 
The present paper is devoted especially to the situation and structure 
of the laticiferous network of the Liguliflore, which he finds to be 
situated in the layer of cells previously denominated by him the 
pericycle, situated between the endoderm and the first sieve-tubes of 
the fibrovascular bundles of the central cylinder. This network does 
not belong to the liber, being separated from the sieve-tubes which 
constitute the outermost portion of it by the entire thickness of the 
sclerenchymatous bundle. From here it may extend right and left, 
and may even penetrate between the liber and the sclerenchyma, the 


* Flora, Ixvii. (1884) pp. 113-28, 129-36 (2 pls.). 
+ Bull. Soc. Bot. France, xxx. (1884) pp. 310-3. 


768 SUMMARY OF CURRENT RESEARCHES RELATING TO 


internal cells of the pericycle remaining for a time in a merismatic 
condition, and then becoming differentiated here and there into 
laticiferous cells. 

The isolated resinous cells of the Tubulifloree, which contain a 
laticiferous and resiniferous secretion, occupy precisely the same 
position, differing from them only in their form and in their mutual 
relations. 


Chemical Constituents of Plants.*— M. Ballo is of opinion that 
oxalic acid has a much more important function in vegetable physi- 
ology than is generally supposed; the carbohydrates being formed 
from the reduction of this and other vegetable acids rather than by 
direct synthesis from carbonic acid and water. Tartaric acid, on the 
other hand, is a product either of the oxidation of carbohydrates or 
of the reduction of oxalic acid, as is also the glycolic acid which 
occurs in unripe grapes and in the leaves of the wildvine. As regards 
all other products of oxidation, the less the amount of oxidation, the 
more complicated is the product and the more nearly related to the 
original substance; while, when oxidation is carried on further, we 
get the original substances by which the plant is nourished. The 
vegetable acids are the most common products of oxidation in the 
plant. A portion of the oxalic acid is used in the decomposition of 
calcium sulphate, the rest as the raw material for the production of 
glycolic, tartaric, malic, succinic, and other acids. 

If formic acid is heated with nitric acid, it is oxidized into 
carbonic acid and water, the nitric acid being reduced to nitrous 
oxide ; but at the commencement of the process oxalic acid is formed ; 
and the author believes that this process takes place in nature, 
according to the equation :— 


2 H, CO, + O = H, ©, O, + H, O; 


and that this is one of the reasons why nitrates are so valuable to the 
growing plant. In the living plant a portion of the nitrates is used 
in the production of ammonia and other substances nearly related to 
it, and another in the conversion of amide-compounds into alcohol- 
compounds. The greater part is reduced to the state of nitrous oxide ; 
and from this nitric acid is again formed through the agency of 
oxygen and water. Hence a small quantity of nitrates can bring 
about the formation of a large quantity of oxalates. 

Electric currents exist without doubt in the living plant, and it is 
possible that in some cases these may be converted into chemical 
work consisting in the decomposition not merely of water but also of 
salts. The products of decomposition of these salts may cause the 
formation of metal-derivatives at the negative pole, of derivatives with 
negative radicals at the positive pole. Hlsewhere these substances 
may again combine with one another, and the same process be then 
again repeated. Hence the comparatively small quantity of inorganic 
salts found in plants. 


* Ber. Deutsch. Chem. Gesell., xvii. (1884) p. 6. See Naturforscher, xvii. 
(1884) p. 123. 


ZOOLOGY AND BOTANY, MIOROSCOPY, ETO. 769 


Structure of Leaves.*—E. Mer has studied the cause of the 
different forms of cells in terrestrial and in aquatic leaves. The 
structure of a leaf with a well-developed blade and petiole, in which 
the normal position of the former is horizontal, is due to its situation. 
The upper face receives a large amount of light, and is in conse- 
quence well nourished, and the cells of the upper parenchyma acquire 
a great increase in length, or become palisade-cells. The epidermal 
cells of the upper surface, well nourished in consequence of their 
vicinity to the assimilating parenchyma, increase actively and regu- 
larly, and acquire polyhedral forms, with thick walls and a still 
thicker cuticle; the active development of which they are the seat 
prevents the accumulation in them of food-materials and the forma- 
tion of stomata. The parenchyma of the lower surface receives less 
light and is in consequence less well nourished. Its cells grow 
transversely, and finally separate, leaving between them larger or 
smaller lacunz; their walls sometimes become slightly wavy. The 
cells of the hypodermal layer of the lower surface do not increase in 
length transversely nearly so much as those of the upper surface, 
and even become rounded. 

The hairs originate in the bud, and chiefly on the lines of maximum 
nourishment, the veins. The stomata always make their appearance 
at the end of the hyponastic or commencement of the epinastic 
period, during that phase of development included between the com- 
mencement of the increase in length of the palisade-cells, and the 
appearance of the waviness in the epidermal cells of the lower surface. 

In the submerged leaves of aquatic plants the sinuosity of the 
walls of the epidermal cells is due to insufficiency of nutriment. 


Transparent Dots in Leaves.j—P. Blenk has made an ex- 
haustive examination of the transparent dots in the leaves of a very 
large number of plants belonging to a great variety of natural orders, 
from the point of view of their structure and mode of development, 
and especially of their value in classification. He considers that too 
little account has hitherto been taken of their presence or absence by 
systematists, the anatomical structure which results in the formation 
of these dots being often a point of great importance, which may even 
be made use of in dried specimens. For example, cells with mucila- 
ginous cell-wall in the interior of the leaf occur only in Anonace» 
and Laurinex, and may possibly indicate a close relationship between 
these orders. 

The various causes of transparent dots or lines in leaves are the 
following :—Secreting cells, round intercellular secreting spaces of 
either lysigenous or schizogenous origin, secreting passages, epider- 
mal or parenchymatous cells with mucilaginous cell-walls, cells con- 
taining mucilage, raphides-cells, cells with single crystals or clusters 
of crystals, cystoliths, spicular cells, branched sclerenchymatous 
bundles, groups of sclerenchymatous cells, depressed pits with or 


* Bull. Soc. Bot. France, xxx. (1883) pp. 110-30. 
t Flora, Ixvii. (1884) pp. 49-57, 97-112, 136-14, 204-10, 223-5, 275-83, 
291-9, 389-49, 355-70, 371-86. 


770 SUMMARY OF CURRENT RESEARCHES RELATING TO 


without hairs, crevices in the tissue, stomata. The secreting cells, 
spaces, or passages may contain resin, gum-resin, balsam, or an 
essential oil. 

Secreting cells are an extremely common cause of transparent 
dots, and are usually characteristic of whole families or at least of 
genera. Round intercellular secreting spaces may be lysigenous, as 
in Rutacez, or schizogenous, as in Hypericinee, the two kinds show- 
ing no difference in the mature condition. Both kinds are of great 
importance from a systematic point of view, furnishing distinguishing 
characters for entire families. Thus lysigenous secreting spaces 
occur in the Rutacew, Myoporinee, and Leguminose ; schizogenous 
are constant in the Hypericineze, Myrsineze, Samydex, and Myrtacee. 
Intercellular secreting passages of schizogenous origin cause trans- 
parent lines in a number of Guttifers, and in some species of 
Hypericum. 

Epidermal cells in which the inner wall next the parenchyma of 
the leaf is strongly thickened and mucilaginous cause pellucid dots in 
a number of families and genera. Cells in the interior of the leaf 
with all the cell-walls strongly mucilaginous occur in Anonaces and 
Laurinez, but not in all the species. Cells with mucilage in the 
interior are found in the Ampelidex, and especially in the American 
species of Cissus. 

Raphides-cells are of great importance systematically. They 
are sometimes replaced by cells with single very long prismatic 
crystals. Transparent dots caused by cystoliths occur in Ficus, 
Momordica, and some Acanthacee. 

Of sclerenchymatous elements the most common are spicular 
cells. Round groups of sclerenchymatous cells also occur, and 
elongated sclerenchymatous bundles ; but all these forms are of com- 
paratively small value systematically. Stellately branched scleren- 
chymatous bundles, the so-called ‘‘internal hairs,’ are constant in 
Nymphea and in the genus Ternstremia. 

The following are only occasional causes of transparent or pellucid 
dots, of but little systematic importance :—Depressed pits in some, 
Capparidez and in Victoria regia ; depressed glands in some Meliacee ; 
rupture of the tissue in some Burseracese, in Nyssa capitata and 
Placodiscus leptostachys ; cells with spherocrystalline deposits of 
calcium sulphate, sodium oxalate, or of an organic substance of un- 
known nature ; the meshes of the network of vascular bundles in some 
Capparidez and Portulacex, and finally stomata. 


Secretory System of the Root and Stem.*—In pursuance of 
previous investigations P. Van Tieghem continues his examination of 
the structure and position of the secretory system in the following 
natural orders:—Umbellifere, Araliacee, Pittosporee, Composite, 
Clusiaceze, Hypericaceze, Ternstroemiacee, Dipterocarpes, Liquidam- 
bareze, and Simarubaces. In the Umbellifere and Araliacexe the 
system, which occurs in the roots, tigellum, and cotyledons, is 


nie ee Soc. Bot. France, xxxi. (1884) pp.” 29-32, 43-4, 112-6, 141-51, 


ZOOLOGY AND BOTANY, MIOROSOOPY, ETO. 771 


continued indefinitely from the cotyledons into the stem and leaves, 
in the pericycle, more or less near to the liber of the vascular bundles, 
but not in the liber itself. The same is also the case in the Pitto- 
sporex. In the root of Ligulifloree (Composite) the laticiferous 
network occupies the internal edge of the liber within the sieve- 
tubes, while in the stem it is situated in the pericycle outside the 
sieve-tubes. In those Tubuliflore which possess a secreting system, 
its position in the roots is the same as in the Liguliflore. The root 
of the Radiate and Liguliflore is altogether destitute both of a 
laticiferous network and of isolated resiniferous cells, although 
possessing an endodermic oleiferous system. 

In the Clusiacew the only regions in which secreting canals are 
not found are the pericycle, which forms in the stem a sclerenchy- 
matous ring, and the primary or secondary xylem of the vascular 
bundles. The Hypericaceze resemble the Clusiacea in the constant 
presence of secreting canals and in their general disposition, but 
differ from that order in their presence in the pericycle. The 
Ternstreemiacee present in this respect a close resemblance to the 
Clusiacee. The Dipterocarpex differ, not only from these orders, 
but from all other angiosperms, in the presence of secreting canals in 
the xylem. In the complicated arrangement of the vascular bundles 
in the petiole they approach Malvacee. 

Liquidambar and Altingia have their entire vegetative structure 
traversed by a system of oleiferous canals belonging to the primary 
liber in the roots, to the primary xylem in the stem and leaves. They 
may be said to combine the root of Anacardiaces with the stem and 
leaves of Dipterocarpew. The Simarubez have canals only in the stem 
and leaves, not in the root. The Dipterocarpee, Liquidambaree, 
and Simarubez have this in common, that the stem and leaves have 
secreting canals localized in the primary xylem; they are dis- 
tinguished from one another by the position of the canals in the 
root; in the Dipterocarpex these are in the primary xylem, in the 
Liquidambarexw in the primary liber; in the Simarube there are 
none. In the only other order which has secreting canals in the 
xylem, the Conifer, they occur only in the root and stem. 


Anatomical Structure of the Root.*—J. Constantin points out the 
great uniformity in the structure of the root as compared with that of 
the stem in the great divisions of the vegetable kingdom; but this he 
attributes to the much greater uniformity in the nature of the en- 
vironment. In differing external circumstances he finds the structure 
of the root to vary in precisely the same directions as that of the stem. 

When a root is fully exposed to the action of light, the thickness . 
of the bark is less than in an underground root, while the central 
cylinder is, on the other hand, more developed. The endodermic 
punctations, so clear in underground roots, become indistinct in roots 
exposed to the light; all the fibrous tissues are more developed, both 
in the central cylinder and in the bark; and lignification has advanced 
considerably further. 


* Bull. Soc. Bot, France, xxxi. (1884) pp. 25-8. 


172 SUMMARY OF OURRENT RESEARCHES RELATING TO 


In roots entirely submerged in water, there is a well-developed 
intercellular system, while the vascular system is less developed. 
When an aquatic plant is transported on to dry land, the intercellular 
system diminishes, while the vessels become more numerous, and 
lignification is carried on further. 


Growth of Roots.*—R. v. Wetistein thus states the laws which 
govern the growth of roots :— 

1. In the first periods of development the growth is uniform ; 
afterwards, from the period of germination, it is localized ; the position 
of the zone of maximum growth varying. It begins at the collar, 
advancing gradually towards the apex, where it ceases. 

2. The nearer the growing region approaches the apex of the root, 
the less rapidly does it advance. 

3. The length of the growing region increases as it approaches the 
apex of the root, attains 2 maximum, and then decreases. 

4. Neither the nature of the environment nor variations in tem- 
perature exercise any influence on the law of growth; even decapitation 
may not essentially alter the course of growth, at least at first. 

5. As long as the region of most vigorous growth has not ap- 
proached within about 4 mm. of the apex, the growth of the young root 
depends only on the elongation of the cells already formed in the seed. 
The first stage of growth is the result of this elongation taking place 
in fresh layers of cells, and the growing region thus advancing towards 
the apex. 

6. When the zone of maximum growth has advanced to within 
4 mm., or less, of the apex, cell-division and elongation of cells 
go on pari passu. In the second stage of growth the cells freshly 
formed near the apex contribute to the growth of the root by their 
elongation. 

7. The first stage of the growth of roots is independent of the 
conduction of reserve-materials from the cotyledons or endosperm. 

8. “Sachs’s curvature” depends on a difference in the growth of 
the two sides of the root. This fact is in harmony with Wiesner’s 
explanation of the occurrence of spontaneous phenomena of nutation 
in other organs. 


Growth in length of decapitated and uninjured Roots.j — 
H. Molisch confirms Wiesner’s statement that roots when deprived 
of their growing point grow less in length than uninjured roots under 
similar conditions of growth; and that this difference of growth in 
length depends greatly on temperature, being inconsiderable when 
the temperature is low. He further believes that the reasons why 
Kirchner has come to a different conclusion are probably that he 
worked at too low temperatures; that he removed too small a 
quantity from the apex of the root; and that the number of ex- 
periments performed was not large enough to arrive at definite 
conclusions. 


* Anzeig. K. Akad. Wiss. Wien, Feb. 14, 1884. See Bot. Centralbl., xvii. 
(1884) p. 359. 
+ Ber. Deutsch. Bot. Gesell., i. (1883) pp. 362-6. 


raed 


ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 173 


Geotropism and Hydrotropism of Roots.*—A. Tomaschek main- 
tains that the degree of geotropism in a root does not depend on the 
rapidity of growth ; nor is it affected even by severe injuries, pro- 
vided the apex of the root is left uninjured. He regards the view of 
Darwin as fully established that the receptivity for the influence of 
gravitation resides in the apex of the root only, and moreover that the 
apex is susceptible to psychometric differences in the environment 
(hydrotropism), and that this susceptibility is conveyed to the adjacent 
parts. 

Water-glands and Nectaries.;—W. Gardiner confirms Sachs’s 
view that the exudation of water from water-glands is entirely due 
to root-pressure, and never takes place with cut organs; although in 
some cases (Fuchsia globosa) an abundant exudation from hairs in the 
vicinity of the water-glands gives the appearance as if it proceeded 
from the latter. Light retards very considerably the exudation of 
water both from water-glands and from those secreting epidermal 
structures which are not dependent on root-pressure. Water-glands 
are, as a rule, much more fully developed in Dicotyledons than in 
Monocotyledons, which may be due to the latter being of a more 
generally aquatic habit. The chief function, both of water-glands 
and of thin-walled epidermal cells placed in connection with a 
vascular bundle, is to allow of the escape of superfluous water, which 
would otherwise cause injection of the intercellular spaces, and even 
rupture of the tissue. 

Nectaries, i.e. structures of whatever morphological value de- 
signed to secrete a saccharine fluid, do not, as Sachs has pointed out, 
discharge their nectar in consequence of root-pressure, but from the 
activity of the cells of the nectary themselves. 

Folds of Cellulose in the Epidermis of Petals.t —E. Kéhne 
describes a number of different ways in which the lateral cell-walls 
of the epidermal cells of the petals are thickened and folded in a 
variety of plants. He discusses the purpose of these foldings, and 
believes it to be merely mechanical, in strengthening the epidermal 
layer of cells. 

Anatomical Structure of Cork-woods.s—A. Gehmacher gives a 
detailed account of the anatomical structure of several extremely 
light woods from the tropics known as “ cork-woods,” viz. Alstonia 
scholaris from India, Bombax Buonopozense from Senegal, B. Ceiba, 
B. pentandrum from India, Eriodendron anfractuosum from India, 
Kerminiera Elaphroxylon from the White Nile, and the very beautiful 
Chinese “ cork-wood,” which comes apparently from the root of a 
Conifer. They all belong to the wood itself, and not to the bark. 


“Filiform Apparatus” in Viscum album.||—W. Scrobischewsky 
describes the “filiform apparatus” of the embryo-sac as very con- 


* Oesterr. Bot. Zeitschr., xxxiv. (1884) pp. 55-9, 

+ Proc. Camb. Phil. Soc., v. (1884) pp. 35-50 (2 pls.). 

t Ber. Deutsch. Bot. Gesell., ii. (1884) pp. 24-9 (1 pl.). 

§ Oesterr. Bot. Zeitschr., xxxiv. (1884) pp. 149-55. 

| SB. Vers. Rus. Naturf. u. Aerzte, Odessa, Aug. 24, 1883, See Bot. Centralbl., 
xviii. (1884) p. 156. 


774 SUMMARY OF CURRENT RESEARCHES RELATING TO 


spicuous in the mistletoe. The division of the nucleus in the 
embryo-sac takes place in the ordinary way. At each end of the 
embryo-sac three cells are formed, three antipodals, two synergida, 
and an oosphere. The seventh nucleus les within the protoplasm 
near the oosphere, and is remarkable for its size and its elongated 
form; this is the nucleus of the embryo-sac. At this period a small 
vesicle is formed in the wall of the embryo-sac in close proximity to 
the synergide, into which vesicle the two synergide project, destroy- 
ing its wall at two spots; the cell-wall which is thus destroyed 
assumes a mucilaginous character, in the form of very slender threads, 
arranged in the form of a cone, and constituting the peculiar “ filiform 
apparatus.” The synergide then also begin to exercise a destructive 
effect on the outer part of the split wall of the embryo-sac; at two 
points, corresponding to the apices of the synergide, openings 
appear through which the pollen-tube can project free into the 
interior of the sac. By careful pressure the “ filiform apparatus ” 
can often be separated from the synergidew. The threads of the 
latter coalesce, after fertilization, into long homogeneous semi-fluid 
masses. 

The function of the synergide is therefore to facilitate the access 
of the pollen-tube to the oosphere (germinal vesicle) by absorption of 
the wall of the embryo-sac. All stages in the division of the nucleus 
can very easily be followed out in the formation of the endosperm of 
Viscum album ; they agree with those described by Strasburger in the 
case of Hyacinthus orientalis. 


Action of Heat upon Vegetation.*—A short note upon this 
subject by A. Barthélemy deals with (1) the action of heat upon the 
development and direction of growth of roots, (2) the action of heat 
upon the phenomena of heliotropism. 

1. One experiment was made upon hyacinths growing in vessels 
of water; it was found that they invariably grew towards a heated 
brazier placed in their vicinity, whereas the leaves grew away from 
the source of heat and towards the window which was brightly 
illuminated. In another experiment a vessel of water was divided 
by a glass partition into two compartments, one of which contained 
hot water while in the other were placed hyacinth roots floating in 
cold water; the roots always grew towards the glass plate, and 
applied themselves closely to it. When the water was coloured by 
means of lampblack it was found that the growth of the roots 
towards the heated compartment was checked—possibly on account 
of the increased conductivity causing the temperature round the roots 
to become more uniform, or by the lessening of the diathermancy 
of the water which would hinder the action of the heat upon the 
roots. 

2. The experiment made to show the action of heat upon helio- 
tropism is described by the author as follows:—A pencil of solar 
rays was made to fall either directly or by a mirror upon a Dipsacus 
placed in a vase in a dark room ; the stalk rapidly bent towards the 


* Comptes Rendus, xcviii. (1884) pp. 1006-7. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 775 


source of light, but rapidly recovered as if by a rebound as soon as 
the light was removed and the roots of the plant watered. 


Relation of Heat to the Sexes of Flowers.* —T. Meehan 
referring to his former communication f as to male flowers entering 
on active growth at a much lower temperature than the female, 
exhibited catkins and flowers of the European hazel (Corylus avellana), 
which, for the first time in several years, had perfected themselves 
contemporaneously. The past winter had been distinguished by a 
uniform low temperature the entire season. In other years a few 
warm days in winter would advance the male flowers so that they 
would mature weeks before the female flowers opened: hence the 
females were generally unfertilized, and there were few or no nuts. 
Under this law, it was evident, amentaceous plants could not abound 
to any great extent in countries or in localities favourable to bringing 
forward the male flowers before there was steady warmth enough to 
advance the female. He thought this was likely to be the reason 
why so many coniferous trees under culture in the vicinity of 
Philadelphia bore scarcely any fertile seed in their cones—a fact 
which had often been remarked in connection especially with the 
Norway spruce. The male flowers would mature before the female 
had advanced far enough to be receptive of the pollen. 


Influence of Light on the Structure of the Leaves of Allium 
ursinum.t—C. Musset has investigated the truth of the statement 
that light has an influence on the leaves of certain plants, and finds 
that, in Allium ursinum, at any rate, there is no change in structure 
which can be ascribed to the action of light. 


. Effect of Light and Shade on Pine-leaves.s—E. Mer describes 
at length the difference in the development of the “needles” of Abies 
excelsa, according to their position on the tree or the branch, and 
according to whether the tree stands alone or is closely surrounded 
by others, depending therefore on the amount and the direction of the 
light which falls on the leaves. 


Movement of Water in Plants.|\—As a contribution towards our 
knowledge of the causes of the movement of water in plants, 
J. Dufour has made a series of observations of the relation between 
the size of the cell-cavity and the thickness of the cell-walls in a 
number of woody plants, with the following approximate results :— 
Sambucus nigra, cell-cavities (without vessels) 16-18-8 per cent., 
walls of wood-cells, 81:2-84 per cent.; Fagus sylvatica, diameter of 
- vessels 7°4, cell-cavities 7:5, xylem-parenchyma 17-0, cell-walls 
68:1 per cent.; Hamatoxylon campechianum, cell-cavities 4.-8-23-0, 
cell-walls 77-95°2 per cent.; Cosalpinia echinata, cell-cavities 4+ 2- 
14-0, cell-walls 86-958 per cent.; Alnus incana, cell-cavities 43+ 5- 


* Proc. Acad. Nat. Sci. Philad., 1884, pp. 116-7. 

¢ See this Journal, iii. (1883) p. 532. 

} Comptes Rendus, xcviii. (1884) pp. 1297-8. 

§ en ng trees rig ote ae (1883) pp. 40-50. 

|| Arbeit. Bot. Inst. Wiirzburg, iii. (1884) pp. 36-51 and Arch. Sci. Phys. 
Nat., xi. (1884) p. 15. Cf. this Journal, ante, p. 414. eg 


776 SUMMARY OF CURRENT RESEARCHES RELATING TO 


51-6, cell-walls 45-8-56°5 per cent. ; Buxus sempervirens, cell-cavities 
of wood-cells 7°9, cavities of vessels 9°8, walls of vessels and cells 
82°83 per cent.; Morus alba, cell-cavities (without vessels) 10-6—25 ; 
cell-walls 75-89:4 per cent. 

The author retains his opinion that the cell-cavities and vessels of 
wood are in no way necessary for the transport of the sap. This 
movement takes place entirely in the cell-walls, in consequence of a 
little-known property belonging to their internal nature. It is, no 
doubt, to a certain extent influenced also by transpiration. 


Movement of Water in the Wood.*—Both the prevalent theories 
with regard to the causes of the ascent of the sap in woody plants— 
that of imbibition, that it ascends through the porous walls of the 
vessels, while the cell-cavities are filled with air, and that of gas- 
pressure, that at the time of greatest transpiration the vessels are 
filled partly with sap, partly with bubbles of rarefied air—depend on 
the hypothesis that the cell-cavities or vessels of the wood contain air 
under normal conditions. M. Scheit throws grave doubts on the 
elementary fact on which both these theories are founded. The air- 
bubbles constantly found in the vessels in microscopical sections have 
probably entered in the process of dissection, and those said to have 
been observed in sections under oil are certainly in some cases bubbles 
of aqueous vapour. There are only two possible ways in which air 
can reach the tracheids, through the stomata or through the root. 
The first hypothesis is excluded by the fact that there is no direct 
connection between the stomata or the intercellular spaces and the 
vessels; the second is very improbable; it is difficult to understand 
how air could pass through the fluid which permeates the parenchyma 
and collect in bubbles. By a number of actual experiments on Abies 
balsaminea and eaxcelsa, Taxus baccata, Acer platanoides, and Péeris 
aquilina, Scheit also determined the impermeability to air of moist 
wood and of the closing membrane of pits; the water-conducting 
organs contain nothing but water either in the liquid or gaseous state. 

The author believes that the passage of water from the parenchyma 
into the tracheids is greatly facilitated by the bordered pits. The 
water is absorbed from the soil by the youngest parts of the roots and 
the root-hairs by means of osmose; the osmotic pressure is greatest 
at the thinnest spots of the cell-wall, the pits; and, as far as the 
elasticity of the closing membrane of the pits permits, this membrane 
is pressed in towards the cavity of the adjoining vessel, and brought 
into a position for filtration, so that water can now readily pass into 
the vessel. The manometer indicates that this root pressure may 
amount to as much as one atmosphere. The water thus pressed 
into the empty vessels rises through capillarity, and the root pressure 
has thenceforward nothing more to do than to place the closing 
membrane of the pits in a position for filtration ; a continuous column 
of water being thus formed in the plant. The whole plant is per- 
meated by a system of capillary tubes having its lower end in a tissue 
which absorbs water, the parenchyma of the root; its upper end in a 


* Bot. Ztg., xlii, (1884) pp. 177-87, 193-202. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 777 


tissue which gives off water, the spongy parenchyma of the leaf; in 
the other parts of the plant this system is accompanied by the paren- 
chyma of the wood and medullary rays, which latter convey to the 
cortex the water required by it; while in the stem the whole conduct- 
ing apparatus is also enveloped by cambium. 


Measurement of Transpiration.*—Under the name Potetometer 
J. W. Moll describes an instrument invented by him for the purpose 
of exactly measuring the quantity of water given off, in any space of 
time, by the foliage of plants. 


Exhalation of Ozone by Flowering Plants.t—A series of ex- 
periments conducted by Dr. J. M. Anders go far to prove that flower- 
ing plants, especially odoriferous ones, give off ozone under the 
influence of sunshine. Schénbein papers suspended in glass cases 
with flowering plants showed under favourable conditions marked 
blue shades, and though Dr. Anders does not wish to say dogmati- 
cally that all the changes seen in the test-papers were produced by 
ozone, he considers it incontestable that this substance was the chief 
agent in their production. 

With regard to the probable mode of its production, Dr. Anders 
concludes that “during the formation of the seeds there is a rapid 
metastasis of phosphorites, in the form of phosphoric acid, and the 
phosphates to that organ of the plant, and it may be reasonably 
supposed that in the chemico-vital changes going on in the ovules, 
phosphorus is liberated and acted upon by the moisture which the 
leaves and petals are so actively transpiring.” Under these circum- 
stances it not improbably follows that those flowers which produce 
the most seed are the largest generators of ozone, so that the sunflower 
may have other than esthetic claims to our admiration. 


Acids in the Cell-Sap.t—G. Kraus has examined the relative 
proportion of acid in different plants, in different parts of the same 
plant, and in the same part at different times of the day. As a rule, 
in most woody and herbaceous plants, the leaves contain the largest, 
the root the smallest quantity of free acid, though there are exceptions 
to the rule. In the stem the acidity increases from above downwards, 
or, in other words, increases absolutely with age. He regards the 
acids as not mere products of excretion in metastasis, but as playing 
an important part in the processes of life. In geotropic curvatures 
the amount of free acid is both relatively and absolutely less on 
the convex side. 

The formation of acid is, as a general rule, hindered by light. 
As regards periodicity, the maximum of free acid is found in the 
early morning; the amount then decreases steadily till the evening, 
when it reaches its minimum, increasing again gradually during the 
night. 

* Arch. Néerl. Sci. Exact. et Nat., xviii. (1883) pp. 469-78 (1 pl.). 

+ Amer. Natural., xviii. (1884) pp. 337-44, 470-7, Of. Engl. Mech., xxxix, 


(1884) pp. 313-4. 
$ Abh. Naturf. Gesell. Halle, xvi. (1884), See Bot. Centralbl., xviii. (1884) 


p- 100. 
Ser, 2.—Vou. LV. 3 RK 


778 SUMMARY OF CURRENT RESEARCHES RELATING TO 


The most abundant acid in the sap is malic, occurring either free 
or as calcium malate; the amount of this salt appears to remain 
nearly constant by day and by night. 

Kraus regards the vegetable acids as secondary products of 
respiration, occurring especially in those parts which contain abund- 
ance of protoplasm, the medium of respiration. He does not support 
the view that they are products of assimilation. 


New Colouring Substance from Chlorophyll.*—R. Sachsse dis- 
tinguishes two varieties of the derivative from chlorophyl] previously 
described by him as phyllocyanin, but which he now prefers to call 
pheochlorophyll, viz.:—a phzochlorophyll, almost insoluble, and 
B pheochlorophyll, soluble with difficulty in alcohol. The latter 
substance is, when dry, nearly black, insoluble in water, soluble in 
alcohol, from which it separates on cooling in amorphous flakes, 
and in benzol. It is distinguished by its peculiar brown-yellow- 
green colour, and its formula is C,;H,,N,0,. 

By heating 8 pheochlorophyll with baryta water or fusing with 
soda, it is deprived of carbonic acid, and a new substance obtained 
with the composition C,;H,;N,0,, which, when dry, is of a dark red- 
brown colour. Its solution in alcohol is dark red, which a few 
drops of sulphuric acid change to light red-violet. The colour itself 
and the spectrum are very similar to those of an alcoholic extract of 
violets. Saturation of an acid solution with alkali gives, however, 
a yellow or, in very concentrated solution, a red colour instead of 
green. Dry distillation with soda gives a crystalline sublimate 
soluble in alcohol.and extremely soluble in ether. 


Crystalline Chlorophyll.j—J. Borodin believes that he has 
obtained the long-desired result of pure chlorophyll in a crystalline 
form by slow evaporation of an alcoholic solution, though he has not 
as yet been able to isolate the crystals. They are doubly refractive, 
giving a beautiful green sheen in polarized light. Their physical 
properties differ from those of the dark-green crystals of hypochlorin 
hitherto obtained. 


Crystals and Crystallites;— By the term crystallites A. 
Famintzin designates structures which agree neither with crystals 
nor with the organized products of living cells. They may be 
arranged under four different types, connected by transitional forms. 

The mode of formation of crystals was illustrated by artificial 
crystals of potassium phosphate and magnesium sulphate. From 
these the author established the following points: (1) The original 
form of the crystal is not always its permanent form. (2) Crystals 
are formed constituting the half or even the fourth of a double 
rhombic pyramid. (3) Crystals do not always grow with flat surfaces, 


* SB. Naturf. Gesell. Leipzig, x. (1883) pp. 97-101. 

+ SB. “Vers. Russ. Naturf. u. Aerzte, Odessa, Aug. 25, 1883. See Bot. 
Centralbl., xviii. (1884) p. 188. - 

{ SB. Vers. Russ. Naturf. u. Aerzte, Odessa, Aug. 24, 1883. See Bot. 
Centralbl., xviii. (1884) p. 158. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 779 


growth frequently taking place by means of irregular prominences. 
(4) Crystals exhibit a splitting both transverse and longitudinal. 


Spherocrystals,*—A. Hansen’s extended paper on this subject is 
now published. A preliminary notice of it was given ante, p. 416. 


Formation and Resorption of Cystoliths.t—Continuing his pre- 
vious investigation of cystoliths, J. Chareyre has examined chiefly 
those of Urtica Dodartii, U. pentandra, Oannabis sativa, Acanthus 
mollis, A. lusitanicus, Thunbergia alata, and Andrographis paniculata, 
grown in different soils, in darkness and in light. He finds all the 
seeds of Urticaces examined before germination to contain reserves 
of food-materials composed entirely of aleurone-grains, in each of 
which is a globoid; and this is also the case with the seeds of 
Acanthacex, except those of Acanthus and of Hewacentris coccinea, 
which have no cystoliths, and in which the reserve food-material 
consists for the greater part of starch-grains. No portion of these 
reserves contributes to the formation of deposits of calcium car- 
bonate, whether as cystoliths or in any other form. Nor are they 
employed in the formation of crystals of calcium oxalate, which 
do not occur in the plants under examination during or in the 
period following germination, When grown in pure silica the 
cystoliths do not attain full development; the pedicle is formed, but 
does not develope cellulose at its apex, and always dies away when 
entirely deprived of lime. Ordinary soil and soil formed of pure 
calcium carbonate are about equally favourable to the formation of 
cystoliths. When grown entirely in the dark, the seeds contain only 
rudimentary cystoliths in which is no calcium carbonate. 

In reference to the influence of the death or etiolation of the leaf 
on the quantity of lime contained in the cystoliths, the author found 
that in the Acanthaces etiolation, and even death, has no effect on 
their formation. Among the Urticaces, and especially Ficus elastica, 
darkness causes, after from 10 to 15 days, complete disappearance 
of calcium carbonate in the cystoliths, this disappearance being 
connected chiefly with the cessation of the function of the chloro- 
phyll. The carbonate is not converted into bicarbonate; and a 
disappearance takes place of calcium oxalate as well as carbonate. 
The lime has entered into combination with some other acid, which 
is probably pectic acid; it disappears from the leayes, and passes 
into the stem, at least partially, in the form of calcium pectate, 


Development of Raphides.t— A. Poli has investigated the for- 
mation of the raphides contained in the cellular tissue of the bulb of 
Narcissus intermedius, where they are always accompanied by a strong 
development of mucilage. They occur in longitudinal rows of cells, 
and in older examples are always imbedded in mucilage resulting 
from the deliquescence of the transverse walls, which mucilage escapes 


* Arbeit. Bot. Inst. Wiirzburg, iii. (1884) pp. 92-122 (3 figs.). 
+ Bull. Soc. Bot. France, xxx. (1883) Sess. Extr., pp. vili—xii. Cf. this 
Journal, iii. (1883) p. 389. 
+ Nuoy. Giorn. Bot, Ital., xvi, (1884) pp. 56-9 (1 pl.), 3 9 
¥ 


780 SUMMARY OF CURRENT RESEARCHES RELATING TO 


from the plant in great quantities when wounded. In the young 
state only a single bundle of raphides is found in each cell, later they 
are much more numerous. 

Here and there, in specimens preserved in alcohol, applied to the 
walls of the cells which contain the raphides were found solid spherical 
bodies of a yellowish colour and finely granular structure. The 
formation of these bodies was unquestionably due to the alcohol; 
and they probably arise from some gummy modification of the 
mucilage. 


New Vegetable Pigment.*—A Rosoll finds in the involucral 
bracts of several species of Helichrysum a hitherto undescribed colour- 
ing substance, to which he gives the name helichrysin. It tinges 
the protoplasm, is soluble in water and alcohol, and is turned a 
purple-red by both acids and alkalies. 

The same writer also describes methods for detecting saponine 
and strychnine in vegetable tissues. The first is easily recognized 
by the action of sulphuric acid, which it colours first yellow, then 
red, and finally reddish-violet. It occurs in the living cells dissolved 
in the cell-sap. Strychnine is coloured an intense violet-red by 
potassium bichromate and sulphuric acid. It occurs in all the cells 
of the endosperm of Strychnos nux-vomica and S. potatorum dissolved 
in a fatty oil. 


Fish caught by Utricularia.j—G. E. Simms has discovered that 
newly hatched fish are caught and killed by the bladder-traps of 
Utricularia vulgaris, ‘They are mostly caught by the head, which is 
pushed as far into the bladder ag possible until the snout touches its 
hinder wall. The two dark black eyes of the fish then show out 
conspicuously through the wall of the bladder. By no means a few 
of the fish, however, are captured by the tail, and in several instances 
a fish had its head swallowed by one bladder-trap and its tail by 
another. : 

Prof. H. N. Moseley ¢ thinks it probable that the fact described 
by Darwin (that the larger of the two pairs of projections composing 
the quadrifid processes by which the bladders are lined project 
obliquely inwards and towards the posterior end of the bladder) has 
something to do with mechanism by which the fish become so deeply 
swallowed. The oblique processes, set all towards the hinder end of 
the bladder, look as if they must act, together with the spring-valves 
of the mouth of the bladder, in utilizing each fresh struggle of the 
captive for the purpose of pushing it further and further inwards. 


* Anzeig. K. Akad. Wiss. Wien, 1884, Nos. 7,9, See Bot. Centralbl., xviii. 
(1884) p. 94. 

+ Nature, xxx. (1884) pp. 81 and 295-6 (8 figs.). 

t Ibid., p. 81. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 781 


B. CRYPTOGAMIA. 


Cryptogamia Vascularia. 


Anatomy of Vascular Cryptogams.*—P. Van Tieghem has 
studied several points in the anatomy of vascular cryptogams, recent 
and extinct. The secondary tissues of cryptogams, like those of 
phanerogams, proceed normally from two concentric generating 
layers ; an external one in the cortex, forming bark outwardly, and 
secondary cortex inwardly; an inner one in the central cylinder, 
intercalated in the liber and in the xylem of the primary vascular 
bundles, producing secondary liber outwardly, and secondary wood 
inwardly. The normal subero-cortical generating layer is well de- 
veloped in the stem (Botrychiwm, Helminthostachys), root (Botrychium, 
Helminthostachys, Angiopteris, Marattia), and leaves (Botrychium, 
Angiopteris, Marattia). The normal libero-ligneous generating layer 
is developed both in living ferns (Botrychium, &c.) and in extinct 
vascular cryptogams, as Sphenophyllum and Sigillaria. In addition 
to these normal layers we find in certain species two other abnormal 
generating layers: one external to the primary vascular bundles 
(Zsoetes), and one interior to the primary vascular bundles (Boiry- 
chium). 

The author also describes several anomalies in the primary 
structure of the root, viz. in the principal trunk and in the branches 
of a dichotomous root. 


Fertilization of Azolla.j—E. Roze has studied the structure of 
the androspores (microspores) and gynospores (macrospores) and the 
mode in which fertilization is effected in Azolla filiculoides, but 
without adding anything fresh of importance to what is already 
known. He observes that the barbed hairs attached to the “ massule ” 
as they escape from the androsporangium do not occur throughout 
the whole genus, being wanting in Azolla pinnata and nilotica. The 
internal membrane of the gynosporangium, which remains attached 
to the gynospore in the form of a funnel, appears to play an important 
part in fertilization in facilitating the access of the antherozoids. 


Muscinee. 


Male Inflorescence of Mosses.{—H. Satter confirms the observa- 
tions of Leitgeb and Kiihn in the case of Fontinalis and Andreca, that 
the axil of the shoot is used up in the formation of the antheridial 
receptacle, Leitgeb regarding this to be the rule with mosses. Tho 
author shows that this is also the case with many Bryines, also 
with Phascum and Archidium, which display apparent exceptions to 
the rule. 

In Phascum cuspidatum the last three segments and the apical cell 


* Bull. Soc, Bot. France, xxx, (1883) pp. 169-80, 
+ Ibid., pp. 198-206 (1 fig.). 
t Ber. Deutsch. Bot. Gesell, ii. (1884) pp. 13-9 (1 pl.). 


782 SUMMARY OF OURRENT RESEARCHES RELATING TO 


form antheridia; behind the three leaves which are formed earlier 
lateral shoots arise, or more often behind the youngest of them only, 
and always behind the cathodal half of the leaf-forming segment. 
After the formation of usually only three whorls of leaves, these pass 
over to the formation of archegonia. In the leaves behind which the 
shoots arise the formation of a midrib is suppressed, and they are 
subject also to a variety of displacements in their insertion. The first 
of the archegonia is formed out of the apical cell, the three or four 
others out of the youngest segments. When the sexual organs are 
mature, the female branch projects only slightly above the male 
inflorescence; it is only after impregnation that any considerable 
elongation takes place, by which the male inflorescence is pushed to 
one side, or comes to stand in the fork, and is then surrounded by 
two involucral leaves. 

The process is the same in Archidium phascoides, only that there 
is no considerable elongation of the female shoot; and hence the 
archegonia and antheridia are apparently inclosed in a common peri- 
cheetium composed of involucral leaves. 

The same relative position of the sexual organs is exhibited by 
Pottia subsessilis, P. cavifolia, P. truncata, P. minutula, P. Heimit, 
Distichium inelinatum, Desmatodon obliquus, D. Laureri, and Oreas 
Martiana. There is in these cases no doubt that the antheridial 
receptacle is the termination of the main axis, and that is pushed 
aside and overgrown by the elongation of the female branch. 

A modification of this arrangement is exhibited by many species, 
as Orthotrichum crispulum, O. Hutchinsie, Bartramia Halleriana, 
B. pomiformis, Amblyodon dealbatus, &c., where the lateral shoots do 
not arise immediately beneath the male inflorescence, but in lower 
whorls of the male shoot. Hither these lateral shoots form archegonia 
at once, or antheridia are again formed through several generations 
of shoots, archegonia only in a later generation. In Amblyodon these 
last branches are not always exclusively female, but have often sexual 
organs of both kinds united in the same inflorescence. The author 
considers that such a hermaphrodite inflorescence consists of two 
independent shoots, the female one being formed immediately beneath 
the antheridium-bearing segments, without producing any vegetative 
segments, proceeding directly to the formation of archegonia; this 
view being confirmed by transitional forms. 


Lesquereux and James’s Mosses of North America.*—This book 
includes all the mosses which are known on the North American 
continent within the limits of the United States and northwards. 
900 species are dealt with, a very large portion of them being 
EKuropean. The classification does not diifer materially from that of 
Bruch and Schimper (used in Wilson’s ‘ Bryologia’). The definitions 
of species and genera are commendably full and clear, and the authors 
have avoided establishing or admitting species upon a slender founda- 
tion of differential character. 


* Lesquereux, L., and T. James, ‘Manual of the Mosses of North America,’ 
447 pp: and 6 pls. 8vo, Boston, 1884. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 783 


Fungi. 
Supposed Absorption and Disengagement of Nitrogen by Fungi.* 


—G. Bonnier and L. Mangin detail a series of experiments by which 
they claim to have proved that the statement that fungi both absorb 
and give off nitrogen while in a state of vegetative activity is founded 
on error. The process of respiration consists solely in a disengage- 
ment of carbon dioxide. 


Fungus parasitic on Drosophila.t—The Rev. J. L. Zabriskie 
describes Appendicularia entomophila Peck, a new fungus parasitic on 
the fly Drosophila nigricornis Loew. It is closely related to the 
Spheronemei of the Coniomycetes. Like Spheronema, the fruit has 
a bulbous conceptacle, surmounted by a long beak perforated at the 
apex, where the spores ooze out in a globule; but, unlike any de- 
scribed Spheronema, this has the conceptacle seated* upon the broad 
summit of a pedicle as long as the conceptacle itself; and also on one 
side of the summit of the pedicle and at the base of the conceptacle, 
it has an erect, leaf-like appendage, with strongly serrate margins, 
like a white-elm leaf folded along its midrib. The pores are slender, 
pointed at each end, and divided by a septum into two unequal 
cells, one cell being twice as long as the other. The total length 
of the fruit is from +02 to ‘03 in., and that of the spores from -001 
to ‘002 in. The conceptacles of the fungus project directly from 
different points of the surface of the fly; so that they are found in 
all positions—erect, horizontal, and dependent. They grow some- 
times singly, but oftener in clusters of two, three, or more, and are 
found most frequently on the tibie of the hind legs, but also springing 
from the inner posterior surfaces of the abdominal rings, from the 
costal vein of the wing, from the head, and from the thorax. One 
fly had about fifty of these conceptacles on various parts of the body 
and limbs. 


Peronosporee.t—M. Cornu gives (1) a monograph of the parasite 
of the lettuce, Peronospora gangliiformis, (2) an important memoir on 
the Peronospora of the vine. In both memoirs the best modes of 
treatment are discussed for checking or warding off the disease. 


Vine-mildew.$—E. Prillieux has observed on Peronospora viticola 
reproductive bodies of a peculiar kind which he regards as probably 
intermediate between the ordinary conidia and oogonia. They appear 
in the same position as the conidia, emerging from the stomata of the 
leaf, and consist of short filaments terminating in pear-shaped bodies 
considerably larger than the ordinary conidia and separated from the 
pedicel by a septum. Their germination has not been observed. 

The author is of opinion that the ordinary “rot” or “ grey rot” 
of the American vines is produced by Peronospora viticola, and not by 


* Bull. Soc. Bot. France, xxxi. (1884) pp. 19-22. 

+ Science, iv. (1884) p. 25. 

¢ Cornu, M., ‘ Observations sur le Phylloxera et sur les parasitaires de la 
vigne.’ See Bull. Soc. Bot. France, xxx. (1883) pp. 36-8. 

§ Bull. Soc. Bot. France, xxx. (1883) pp. 19-24, 228-9. 


784 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Phoma wvicola, as had previously been supposed ; although the latter 
fungus undoubtedly makes its appearance in the berries or seeds 
which have already been attacked by the Peronospora, but it plays 
only a secondary part. 

The germination of the oospores of P. viticola, has further been 
observed by Prillieux. On germinating the oospore gives rise to a 
branching tube which bears a number of conidia. 


New Theory of Fermentation.*—E. Cocardas propounds the 
strange theory that all the different kinds of fermentation—which are 
as numerous as the different kinds of protoplasm—are due to the 
action of a single organism, Penicillium, which appears, according to 
its vital conditions, in the various forms of Bacterium, Bacillus, 
Spirillum, Zooglea, Hygrocrocis, Leptomitus, Torula, Byssus, Mucor, 
Aspergillus, Penicillium, Micrococcus, Microderma, Saccharomyces, &e. 


Microbes in Human Saliva.t—A. F. Rasmussen has made a 
careful examination of the micro-organisms found in the saliva of 
healthy men, with the following results. 

The sources of these microbes—mould spores, ferment-fungi, and 
bacteria—are the air and the food ; some disappear immediately, while 
others remain and undergo further development. 'The temperature 
of the mouth, 36°-37° C., is very favourable for their development, 
nutrient substances and oxygen being also always present in great 
abundance. The organisms are especially abundant at the outer side 
of the base of the back teeth, especially in the upper jaw, where a 
thick layer of tough mucilage is always found in the morning, and for 
some time after a meal. Carious teeth also breed large quantities 
of these organisms. 

The author found none of the methods previously used for the 
culture of these organisms satisfactory ; culture on a solid substratum 
he always found the most advantageous. The gelatine used for the 
purpose was placed in bulbs with a large bottom, so as to give as 
large a surface as possible. The staining employed was sometimes 
Koch’s method, sometimes potassium biniodide, which however caused 
great changes in the size of the objects. Thus the sporiferous 
segments of Clostridium polymyxa measured 4—6 « before, 2-2 to 2°4 
after staining. The reagent for Leptothriz employed was potassium 
biniodide with a small quantity of hydrochloric acid. 

The bulbs and test-tubes used were purified by concentrated 
sulphuric acid and distilled water, or with dilute (0-1 per cent.) solu- 
tion of corrosive sublimate; and the wad-plugs used to close the 
apparatus were sterilized by a temperature of 110-120° C. For 
culture in nutrient fluids the author used the bulbs recommended by 
Salomonsen ; various fluids were used, as human urine diluted with 
water and boiled for ten minutes, then filtered and neutralized with 
sodium carbonate, bouillon, solution of peptone, beer-wort, solution of 


* Bull. Soc. Bot. France, xxxi. (1884) pp. 12-8. 
+ Rasmussen, A. F., ‘Om Dyrkning af Mikroorganismen fra Spyt af sunde 
Menesker’ (Danish) 136 pp. (2 pls.). See Bot. Centralbl., xvii. (1884) p. 389. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 785 


potassium albuminate, prepared by Lieberkiihn’s method, &e. For 
conveying bacteria from one vessel to another, finely drawn-out glass 
capillaries were used, first sterilized in a flame. 

The author describes the culture of the microbes on potatoes, 
turnips, and on rye-bread; and rules are given for the preparation of 
the nutrient substance, the method of Koch and Brefeld being essen- 
tially followed. After a longer or shorter time small patches, dots, 
elevations, cushions, and similar structures arise, due to the microbes 
propagated from the saliva. These may be either (1) white moist 
opaque elevations—micrococci and bacteria, or (2) grey, dry, some- 
what transparent patches—bacilli, colonies of a leptothrix-ferment, or 
oblong cells; torula and round saccharomyces-cells constitute a 
transition between the two; Penicillium glaucum, Oidium lactis, and a 
few species of Mucor were also met with, but the colonies of these 
forms are very easily confounded with those named before. 

Culture on nutrient gelatine closely resembles that on potatoes ; 
but many of the cultivated organisms deliquesce on the surface of 
gelatine; this is the case with the chromogenous bacteria, the spori- 
ferous bacilli, Penicillium, and Cladosporium. In the gelatine-culture 
other phenomena also present themselves. Some forms grow down- 
wards towards the bottom of the vessel, and form wedge-shaped 
figures; torula puts out lateral branches from these wedges; other 
forms spread out horizontally over the bottom; Micrococcus luteus 
forms delicate pellicles, from which threads branch vertically down- 
wards; Bacillus Ulna forms a kind of diffuse infiltration, which 
descends into the gelatine and decomposes it on the surface. Culture 
upon gelatinized serum presented no very distinct peculiarities. 

As regards the systematic position of the microbes observed, the 
author speaks first of the Zygomycetes, Mucor racemosus and 
stolonifer ; also M. spinosus, new to Denmark, but observed only 
once. In all cases they had the faculty of forming torula-cells. 
Among Ascomycetes, Penicillium glaucum and album were observed, 
and among Hyphomycetes, Cladosporium herbarum, and Oidium lactis, 
the latter being one of the most frequent of the saliva-organisms. 
Torula was also found abundantly in nutrient fluids, and on gelatine 
and potato; when transferred to solutions of grape-sugar or to diluted 
urine, it exhibited no power of fermentation or of inverting, Under — 
the name “torulose cells” (hefedhnliche Zellen) the author describes 
colourless or reddish cells, either roundish or elongated, and also 
peculiar species of Saccharomyces, which are only stages of develop- 
ment of higher fungi. One of these flesh-coloured species appears to 
be allied to Cohn’s Saccharomyces glutinis ; a second unnamed form 
was 9-11 p long, 4 » broad, with drops of oil imbedded in the proto- 
plasm; a third consisted of round and elongated cells arranged in 
colonies, 11 » long, and 3 » broad, with no drops of oil. Saccharo- 
myces apiculatus was not observed. 

With regard to the Schizomycetes, the author considers that the 
view of Zopf that the different forms are stages of development of the 
same organism is true only of Leptothrix, which may go through all 
the yarious forms, while all the other Schizomycetes have one form 


786 SUMMARY OF CURRENT RESEARCHES RELATING TO 


only. Of these constant forms he finds Bacillus Ulna, Clostridium 
butyricum, O. polymyxa, and several others not named, but no constant 
bacterium, and only once a coccus. 

Of Leptothria three distinct forms are described in detail, one of 
them chromogenous. Two of these he regards as comprised under 
L. buccalis, which together with spirillum, vibrio, and Spirocheete 
denticola, causes the mucilage of the teeth. 

Of other chromogenous forms the author finds Micrococcus luteus, 
two unnamed, and Bacillus Hansenii, a new species. Cultivated on 
potato, this form grows with extraordinary rapidity, almost to the 
exclusion of all others. 

Experiments are described which lead to the conclusion that the 
fluid in some cases contains micro-organisms when it enters the 
mouth from the ductus stenonianus; but that the air expired from 
the lungs is free from them. 


Microbia of Milk.*—F. Hiippe has made a detailed examination 
of the microbia of milk, which can, he states, be completely sterilized 
by a temperature of 75°-100° C. He describes in detail the bacteria 
connected with the fermentation of milk, their biological relationships, 
and their chemical action on the milk. The bacilli of butyric fer- 
mentation are also described, the organisms of blue milk, other 
pigment-forming bacteria, mucilaginous milk, and Ozdium lactis. The 
author holds very strongly the view of the constancy of the bacteria 
of milk. 


Microbe of ‘‘ Morbillo.”+—-M. Lanzi has investigated the microbe 
characteristic of this infection which he finds especially in the desqua- 
mated scales of the skin and in the urine. He considers it to be a 
species peculiar to this complaint, to which he gives the name 
Bacterium morbilli with the following characters :—Cells round or 
elongated, colourless, motile, isolated or united into chains of various 
lengths, composed of two or more cells, straight or more often curved, 
and even spiral: cells, 0:8-1-0 « in diameter, with the length vary- 
ing from this to double as much; no zoogloea-form was observed ; 
propagation by fission in one direction, and then forming spores. 
Occasionally a large bacillus-form was assumed. The best staining 
reagent was found to be methyl-violet. Bacterium morbilli has no 
power of causing fermentation in the urine like Micrococcus uree. 
Without considering the question decided, the author leans to the 
opinion that it is the cause, and not merely the accompaniment of 
the disease. 


Bacillus of Cholera.{—T. R. Lewis denies the validity of Dr. 
Koch’s conclusions as to the “ comma-shaped ” bacillus being the cause 
of cholera, as bacilli identical in size, form, and in their reaction 
with anilin dyes with those found in choleraic dejecta are ordinarily 
present in the mouth of perfectly healthy persons. 


* MT. K. Gesundheitsamtes, v. p. 309. See Naturforscher, xvii. (1884) 


p. 201. 
+ Bull. Accad. Med. Roma, ix. (1883) No. 7. 
{ Nature, xxx. (1884) pp. 513-5. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 787 


Rabies.—The Government committee appointed to inquire into 
the experiments of M. Pasteur, report that his statements have been 
entirely borne out. Inoculation with the attenuated virus of hydro- 
phobia gives a dog immunity from the disease, just as similar treat- 
ment preserves a sheep from charbon. All the 23 dogs submitted by 
M. Pasteur as having been thus inoculated have resisted the strongest 
virus on inoculation, whereas the majority of the 19 non-inoculated 
dogs have succumbed. Of the latter, six were bitten by mad dogs, 
three of them becoming mad, eight were subjected to intravenous 
inoculation, all becoming mad, and five to inoculation by trepanning, 
all becoming mad. The result is decisive; but the committee will 
now inoculate a large number of fresh dogs, and will compare these 
with an equal number of dogs not inoculated. It will likewise investi- 
gate the question whether, after a dog has been bitten, inoculation 
with the attenuated virus will prevent any consequences from the 
bite. 


Etiology of Tuberculosis.*—Dr. G. N. Sternberg has repeated 
Koch’s inoculation experiments, and is able to confirm him as to the 
infectious nature of tuberculosis; also as to the presence of the 
bacillus discovered by him, in tubercle nodules in the lungs and in 
tuberculous glands of inoculated rabbits and guinea-pigs (inoculated 
with sputum containing the bacillus from a phthisical patient). 
The experiments of Formad of Philadelphia, by which he claims to 
induce tuberculosis in rabbits as a result of the introduction into the 
cavity of the abdomen of finely powdered inorganic material, have 
also been repeated, with an entirely negative result so far as the 
production of tuberculosis is concerned. 

The conclusion is therefore reached that the bacillus of Koch is 
an essential feature in the etiology of the infectious disease, tuber- 
culosis. 


Bacteria and Minute Algx# on Paper Money.{ —J.Schaarschmidt, 
in consequence of Prof. Reinsch’s discovery t of bacteria and alge on 
coins, has examined Hungarian bank and State notes and Russian one- 
rouble notes, and finds schizomycetes and alge on all of them even 
upon the cleanest. 

The vegetation of paper money is, as the result of his researches, 
composed of the following : Micrococcus, Bacillus, Leptothriz (various 
forms), Bacterium termo, and Saccharomyces cerevisie. Also, very 
rarely, Reinsch’s Chroococcus monetarwm and Pleurococcus monetarum. 


Grove’s ‘Synopsis of the Bacteria and Yeast Fungi.’ §— This 
book reaches us too late to say more than that it is a very handy and 
well-arranged synopsis of the Schizomycetes and Saccharomycetes, 
which cannot fail to be of invaluable assistance to microscopists 


* Abstract of paper read before Section F (Biology) of the Amer. Assoc. Ady, 
Sci., Philadelphia, Sept. 9, 1884. 

+ Nature, xxx. (1884) p. 360. 

¢ See this Journal, ante, p. 428. 

§ Grove, W. B., ‘A Synopsis of the Bacteria and Yeast Fungi and allied 
species.’ 8vo, London, 1884, vi. and 112 pp. (87 figs.). 


788 SUMMARY OF CURRENT RESEARCHES RELATING TO 


interested in its subject, and not the less so that our knowledge 
regarding these organisms is at the present time in so scattered and 
undigested a condition. 


Protochytrium Spirogyre, a new Myxomycete(?).*—A. Borzi 
describes a parasitic organism of very low organization, which he 
finds in the cells of Spirogyra crassa and of a few other nearly allied 
species of alga, rapidly destroying the contents of the cells and 
causing complete disintegration of the filaments, the cell-walls them- 
selves ultimately entirely perishing. The minute masses of proto- 
plasm of which it is composed are completely destitute of cell-wall, 
and display amceboid motions, but without any pseudopodia. They 
derive their nutriment directly from the surrounding protoplasm, and 
may be regarded as plasmodia of very reduced dimensions. They 
are composed of homogeneous protoplasm, within which are very fine 
granulations, and have, therefore, all the characters of an organiza- 
tion the simplest that can be imagined. ‘They compose a true jalo- 
plasm in the sense of modern histologists, constantly altering its 
form in consequence of its amceboid motions. The granulations are 
frequently disposed round a small transparent central areole, which 
represents a true vacuole. It is, however, entirely destitute of true 
nuclei, the minute granulations wanting all the characteristic struc- 
ture of these organisms. The central vacuole is constantly altering 
its position, and alternately contracting and expanding. The princi- 
pal, if not the sole, agent in these amceboid movements appears to 
be the superficial protoplasmic layer. The growth of these organisms 
is rapid, and they attain a diameter of about 40 » in twelve hours. 

The process of nutrition may be divided over two distinct 
periods. In the first the nutriment, derived from the surrounding 
substratum, passes directly into the body of the parasite. In the 
second period, the substances, already ingested and deposited, become 
somewhat elaborated and digested. These two phases can be well 
followed under the Microscope. 

When one of the plasmodia comes into contact with a band of 
chlorophyll, it slowly penetrates into its interior. A small portion 
of the nutrient substance, consisting of protoplasm containing chloro- 
phyll and of starch-grains, becomes at length entirely imprisoned in 
the mass of the plasmodium. 'The ingested substance retains for a 
very short time its original properties. The chlorophyll soon loses 
its green colour; the granules of starch are the last portion to be 
completely absorbed. An excretory portion which is not digested 
is finally expelled. 

The vegetative activity of the plasmodia ceases on the commence- 
ment of the reproductive period; they attain a state of quiescence, 
and the formation of zoosporangia commenecs. The peripheral 
layer of protoplasm becomes thinner and tends to merge in the 
internal portion; its motility at the same time disappearing alto- 
gether. After numerous internal changes in the structure of the 
protoplasm, the contents divide by successive bipartitions, either a 


* Nuoy. Giorn. Bot. Ital., xvi. (1884) pp. 5-32 (1 pl.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 789 


portion or the whole of the protoplasm being used up in the forma- 
tion of zoospores, which process is a very rapid one. On escaping 
from the zoosporangium these bodies are minute pear-shaped or 
ovoid masses of protoplasm, containing granulations, and not invested 
with a cell-wall, provided at one end with a flagelliform cilium, and 
also with a contractile vacuole. In some cases the zoospores are 
unable to escape from their parent cell, and transform themselves 
directly into new zoosporangia. Hither the ordinary zoospores or 
those derived from these secondary zoosporangia, after moving about 
actively for half an hour, lose their cilium, and become transformed 
into an ordinary amceboid mass of protoplasm, with movements due 
to contractions and dilations, in which condition they may be 
described as myxamebe. In this state they not unfrequently come 
together and coalesce, the two vacuoles remaining for a time dis- 
tinct, but finally uniting. The original plasmodia are formed either 
from a single myxameeba, or result from a fusion of several ; and these 
may then propagate themselves for several generations before the 
formation of zoospores. 

Instead of the production of zoospores, the period of vegetative 
activity of Protochytrium is frequently closed by the formation of 
cysts, or true encysted plasmodia, especially at the period when the 
host naturally dies. These are cells with double walls, and with a 
considerable space between the outer and inner walls; this space is 
filled with a transparent fluid, often containing small remains of 
nutrient substance not completely digested. The ordinary diameter 
of the cyst itself is from 15 to 25 yw, that of the external envelope 
from 30 to 40 w. This external envelope displays many of the pro- 
perties of fungus cellulose. The internal contents consist of a dense 
finely granular protoplasm. These cysts are formed within the cells 
of the host, and when they decay, fall to the bottom of the water, 
where they germinate after a period of rest, and develope into 
myxamcebe. ‘These again enter the cells of the host by penetrating 
through the cell-walls, in the same manner as the germs of many 
Chytridiacez. 

As regards its systematic position, Protochytrium displays on the 
one hand affinities with the Myxomycetes, and on the other hand 
with such genera of Chytridiacee as Woronina, Rozella, and Olpidi- 
opsis ; but the author considers the entire absence of a cell-nucleus 
to be a point of so great morphological importance that it must for 
the present be referred to Klein’s family of Hydromyxacee, along 
with the forms of Monas described by Cienkowski and Hickel, and 
also Vampyrella, Monadopsis, and Protomyxa. 


Lichenes. 


Substratum of Lichens.*—O. J. Richard, besides combatting the 
theory of an algo-lichenic association, holds that the nature of the 
substratum, whether calcareous, siliceous, metallic, organic, or neutral, 


* Actes Soc. Linn. Bordeaux, 88 pp. See Bull. Soe, Bot. France, xxx. (1883) 
Rey. Bibl., pp. 105-7, 


790 SUMMARY OF CURRENT RESEARCHES RELATING TO 


is of small consequence to the lichen, which derives no nutriment, but 
merely support therefrom. Nor does the author agree that the 
chemical composition of the thallus varies according to the nature of 
the substrata. 


Hymenolichenes.*—This section of lichens was established by 
Mattirolo from the genus Cora, and depends on the symbiosis of an 
alga with a fungus belonging to the class of Hymenomycetes. F. 
Johow has critically examined the group in its native country of 
Venezuela and the West Indies, and includes in it the four following 
genera :— Cora, Rhipidonema, Dictyonema, and Laudatea gen. noy. 
The first three genera must be regarded, from their habit and the 
lamination of their thallus, as heteromerous foliaceous lichens, but 
differing from all other genera in the entire absence of a solid cortex 
and in the unusually complete investment of the alge which perform 
the function of gonidia. Laudatea is distinguished by its peculiar 
cespitose habit, and by the segmentation of the thallus connected 
with it into a saprophytic mycelium and green stems composed of 
bundles of gonidia invested by fungus-hyphe. 

The systematic position of the Hymenolichenes is among the 
Thelephorea, and in near relationship to Thelephora, Corticium, and 
Hypochnus. The only organs of reproduction which they possess are 
sporiferous basidia growing on the under side of unilateral pilei, or on 
crustaceous receptacles (Laudatea). Nylander’s statement of the 
presence in Cora of apothecia has not been confirmed. The saprophytic 
mycelium and crustaceous receptacle of Laudatea find their analogue 
in numerous species of Thelephora and Corticitum. The green foliaceous 
thallus of Cora is homologous to the receptacle of Thelephora. 


Algee. 


Fresh-water Pheospore.t—Under the name Lithoderma fontanum, 
KE. Flahault describes a fresh-water phesosporous alga from the neigh- 
bourhood of Montpellier. It agrees with other species of the genus 
in having the zoosporangia naked and superficial. The thallus is 
closely adherent to the substratum, recalling that of Melobesia or 
Coleochete. The zoospores are ovoid, unequilateral, with a red eye- 
spot and two unequal cilia inserted on the concave side of the zoospore, 
and directed one forwards, the other backwards. They germinate 
directly, without conjugation. 


Nostoc.$—C. Flahault has had the opportunity of examining the 
structure of the rare Nostoc flagelliforme, growing in the neighbour- 
hood of Montpellier, described by Berkeley and hitherto known only 
from Texas. He regards it as identical with the MNematonostoc 
rhizomorphoides of Nylander, which genus must therefore disappear. 
Spores were not observed, but hormogonia frequently. Nostoc flagelli- 


* SB. K. Preuss. Akad. Wiss. Berlin, 1884 pp. 113-28; also Pringsheim’s 
Jahrb. f. Wiss. Bot., xv. (1884) pp. 361-409 (5 pls.). 

+ See this Journal, ii. (1882) p. 542. 

t} Comptes Rendus, xcviii. (1884) pp. 1389-91. 

§ Bull. Soc. Bot. France, xxx. (1883) pp. 89-96 (1 pl.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 791 


forme must also disappear as a species, being merely a variety of 
N. ciniflorum Vauch. 
Flahault further identifies Nostoc coriaceum Vauch. as a form of 


N. ciniflorum. 


New Chromophyton.*—M. Cornu describes an alga coloured by 
a yellow pigment found in a spring of fresh water, in company with 
Navicula, and possessing a siliceous coat similar to that of diatoms. 
He regards it as nearly allied to Woronin’s Chromophyton Rosanoffii,t 
differing from that species in its siliceous envelope, and in the posses- 
sion of stalked bodies which may be sporangia. He proposes for it 
the provisional name Chromophyton Woronini. 


Wolle’s Desmids of the United States.{—The Rev. F. Wolle’s 
work on the desmids of the United States will be found useful by 
English cryptogamists who are not in possession of Ralfs’ work. 
Eleven hundred coloured figures are given illustrating all the species 
and varieties described in the text. 


New Diatoms.—Diatoms from Stomachs of Japanese Oysters.§ 
—F. Kitton describes some new diatoms taken by Mr. G. Sturt from 
the stomachs of some “tinned” oysters from Japan, sent to the 
Fisheries Exhibition, viz., Aulacodiscus Sturtii and Amphipleura 
pellucida var. rectus. Nearly 90 other marine species as well as a 
considerable number of fresh-water species from the stomachs were 
identified by Mr. E. Grove. 

Mr. Sturt’s directions for examining the stomachs of oysters, &c., 
are as follows :—“ After opening the tin and pouring off the liquid 
contents, I empty out the oysters and pick out the stomachs 
(which look like dark little sacs, and as a rule are free, or only 
partially surrounded by a little fatty matter, which is easily taken 
off), I then heat in a glass to boiling point five or six ounces of 
nitric acid, in which I drop one by one the stomachs, waiting until 
each is dissolyed before adding another, After all have been dis- 
solved I add an ounce of hydrochloric acid, and continue the boiling 
for five minutes, dropping in at intervals a little bichromate of potash, 
I now fill up the flask with hot water and empty the whole into a 
large beaker, filling up with the hot water (the fat rises to the 
surface, and on cooling congeals on the top, and is easily skimmed 
off). I wash away the acid, using hot water, and boil in soap and 
water according to Prof. H. L. Smith’s directions, If this does not 
get rid of the organic matter, I boil in sulphuric acid and chlorate of 
potash.” The water used for washing must be filtered rain or dis- 
tilled water and free from all trace of acid, 

Mr. Kitton also describes, from other localities, the following new 
species :—Surirella carinata and Sceptroneis (?) clavus. 


* Bull. Soc. Bot. France, xxx. (1883) Sess. Extr., pp. xciii—yv. 

+ See this Journal, i. (1881) p. 100; iii. (1883) p. 108 and 863, 

; Wolle, F., ‘ Desmids of the United States and list of Pediastrums.’ 168 pp. 
and 53 pls. 8vo, Bethlehem, Pa., 1884. 

§ Journ. Quek. Micr. Club, ii. (1884) pp. 16-23 (1 pl.). 


792 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Structure of Diatoms.*—According to L. Reinhardt a form of 
valve similar to that described by Miller in Triceratium, occurs in 
many, if not all forms with areolated celi-wall. 

The formation of the pedicel and of gelatinous colonies are 
phenomena altogether analogous to those which occur in the palmel- 
loid alge. In the Mastoglea colonies it is easy, when the formation 
of jelly has not advanced beyond a certain extent, to observe a similar 
system of intercalation of cell-walls as in Gloocystis. In the cell-wall 
of Mastoglea and other similar forms, two layers can be distinguished, 
an outer gelatinous, and an inner layer which retains its consistency 
and structure. In the formation of the pedicel the outer layer 
becomes locally mucilaginous. In those forms where an entire group 
of individuals is attached to a single pedicel (as many species of 
Synedra and Liemophora) longitudinal striz make their appearance on 
the thick pedicel corresponding to the separate cells; these are made 
distinctly visible by staining with hematoxylin. 

The author also describes the formation of auxospores in Cocconeis 
communis, Achnanthes longipes, and A. brevipes; in the first species 
their development was followed out in several hundred specimens. 
The auxospores are always formed by the conjugation of two in- 
dividuals, never by rejuvenescence, as stated by Schmitz. The con- 
jugating cells often open at different times, and the formation of the 
mucilaginous bladders begins only with the coalescence of the con- 
jugating masses of protoplasm. The nuclei of the conjugating cells 
move slowly in the direction of the movement of the protoplasm 
towards the anterior margin of the masses of protoplasm, and, a short 
time after these commence to coalesce, a single much larger nucleus 
is seen in the place of the two. Conjugation of the nuclei therefore 
takes place here. ‘The author further describes the formation of the 
perizone and of the cell-wall of the auxospore, the growth and bipar- 
tition of the chromatophores, and the division of the auxospores into 
two primary cells. In Achnanthes longipes the conjugation always 
takes place in a very interesting way between two cells which are not 
equivalent. One of these has always a long pedicel, whilst the other 
is attached by a gelatinous disk to the upper end of the pedicel of the 
first. When the protoplasmic masses of two cells coalesce, a mucila~- 
ginous bladder is formed, which is connected only with the lower 
valve of the stalked cell. Since this bladder is formed essentially 
from the protoplasm of the stalked cell, it follows that that of the 
other cell passes into the bladder of the first. The phenomena in 
this species justify the regarding of the formaticn of auxospores by 
conjugation as a process of sexual reproduction. In A. brevipes the 
process is the same in its general features. The formation of auxo- 
spores without conjugation is regarded by the author as a kind of 
apogamy. 


* SB. Vers. Russ. Naturf. u. Aerzte, Odessa, Aug. 27, 1883. See Bot, 
Centralbl., xviii. (1884) p. 191. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 793 


MICROSCOPY. 
a. Instruments, Accessories, &c. 


Albertotti’s Micrometer Microscope.*—Dr. G. Albertotti, jun., 
has designed the instrument shown in fig. 123, for the purpose of 


measuring microscopic objects more satisfactorily than can be done 
with either eye-piece or stage micrometer. 


Fig, 123. 


If the diverging plates of Helmholtz’s ophthalmometer are inter- 
posed between the eye-piece and objective of a compound Microscope 
in such a way that the axis of the plates is at right angles to the 
axis of the Microscope, the effect of the plates on the apparent 


* Aun. di Ottalmologia, xi. (1882) pp. 29-30 (1 pl.). - 


Ser. 2.—Vou. LV. G 


734 SUMMARY OF CURRENT RESEARCHES RELATING TO 


position of an object seen through the Microscope will be the same as 
when they are used without a Microscope, i. e. so long as the plates are 
in one plane the image is unchanged in its position, but as soon as 
the plates cross at an angle it will be separated into two images of 
equal size, which are displaced in opposite directions. By turning 
the plates through a sufficient angle the displacement can be so 
arranged that the margins of the two images which are turned to each 
other shall coincide, and a compound image is formed which, in the 
direction of the displacement is twice as large as the original 
one. For the same eye objective and eye-piece and for a constant 
distance of both from the axis of the plates, the angle of inclination 
to be given to the plates, in order to double the image, bears a fixed 
relation to the size of the object and may therefore be used to 
measure it. 

If a table is prepared showing the values in mm. of the angles of 
inclination of the plates, it is only necessary in measuring an object 
to turn the plates until the image is doubled and ascertain the angle 
between them, and the table will then give the dimensions. 

In fig. 123 the square box between the eye-piece and objective 
holds the Helmholtz plates which are rotated by the outer milled 
head, the angles of inclination being read off on the large graduated 
drums on each side. 

It is claimed that by the use of this instrument those errors are 
avoided which arise in the use of the eye-piece micrometer if the 
image of the object does not exactly fall in the plane of the 
micrometer divisions. ‘The angles can moreover be read with greater 
precision than the micrometer divisions. 


Baumann’s Callipers with Movable Microscope and Fixed 
Micrometer.*—T. Baumann’s instrument (fig. 124), in which the 
Microscope is movable and has a fixed micrometer in the eye-piece, is 
not intended for such minute measurements as the preceding, but was 
devised for cases for which a vernier is not sufficiently exact, while a 
screw micrometer is too fine or not sufficiently rapid. It will read 
to 0:04 mm. In a base plate A A, 200 mm. long, a central groove is 
cut, along which moves the cylinder a. The upper edges of the 
groove are bevelled off by a cylinder of the same diameter as a. The 
cylinder moves freely along these without attachment of any kind, to 
avoid errors of tension, &c. To one end of the cylinder is attached a 
glass plate C, another glass plate B being fixed exactly parallel at the 
end of A, the two plates forming the jaws of the callipers. The 
cylinder is moved by the ivory handle at h. A plate u wis attached 
to the former on one side, to which plate are fastened the two supports 
g which carry the socket of a compound Microscope Jo (78 mm. high 
and magnifying 50-60 times). The supports g rest on the base plate. 
The socket is divided and the two halves are clamped by the milled 
head m. 'The inside of the socket has a worm so that by turning the 
ring k the Microscope is moved up or down for focusing. 

The edge of the base plate is divided on silver for 150 mm. into 


* Zeitschr. f. Instrumentenk., iv. (1884) pp. 149-52 (2 figs.). 


ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 795 


0:2mm. The centimetres are numbered with large figures and the 
millimetres by microscopic figures from 0 to 9. The approximate 
position of the Microscope is read off by a pointer. One of the 
smaller figures is always in the field of the view, which is 1°5 mm. 
in diameter. At is a micrometer which can be rotated in azimuth. 


Fic. 124. 


wae”) 0 


Its five divisions coincide with one of the scale as seen through the 
Microscope, and each is therefore equal to a fifth of 0:2 mm. or 
0°04mm. The divisions are preferably inclined, as shown in fig. 125. 
The reading in this case is 4°936 mm. as the last line of the micro- 
meter (reading from right to left owing to the inversion of the image) 
is 3-4 divisions from the 4°8 mm. point of the scale. As each 
division is 0°04 mm., 3°4 of these divisions = 0°186 mm. The 


a. @.2 


796 SUMMARY OF CURRENT RESEARCHES RELATING TO 


coincidence of the 0 point of the scale with that of the micrometer is 
obtained by the screws r and s acting on the plate u u, which is not 
rigidly fixed to the cylinder a, but slightly movable. 


Geneva Co.’s Microscope Callipers.—In the instrument, fig. 126, 
(made by the Société Genevoise pour la construction d’Instruments 
de Physique), 2 compound Microscope is made use of for measuring 
minute thicknesses such as cover-glass, &c. It consists essentially of 
a lever at one end of which are the jaws for holding the object to 


Fig. 126. 


be measured (shown in the figure with a piece of glass between 
them), and the movement of which is amplified twelve times. At 
the other end the lever carries a glass plate ruled with 120 divisions, 
which is observed through a Microscope having a fixed micro- 
meter in the eye-piece with 30 divisions. The jaws are opened by 
the milled head on the box, and the extent of movement is indi- 
cated by a scale with 120 divisions (corresponding to the glass plate), 
which passes under the aperture seen at the top of the box. By the 
eye-piece micrometer the principal divisions may be further sub- 
divided. When open the jaws are 8 mm. apart; each of the principal 
divisions represents therefore 1/40 mm., and the subdivisions 
1/1200 mm. The mirror illuminates the divisions of the glass plate. 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 797 


Griffith’s Club Microscope. — Mr, E. H. Griffith writes us that 
he has further improved the ‘ Griffith Club Microscope’ * as follows: 
“The bar that holds the clips has a stiff spring over it. The front 
of the bar is flattened. The clips may be turned back out of the way, 
and when needed again the spring holds the clips down (or the bar 
in position), Some have been made with an arrangement to push the — 
bar either way, letting the bar pass through the stage-holder but 
above it a nut gives the double clips a lateral motion and the spiral 
spring keeps the bar steady. 'The double clips clasp the slide and 
carry it with them. The lamp attachment has been improved 
also.” 


Nachet’s Class Microscope.—This (fig. 127) was intended by M. 
A. Nachet to be passed round amongst the students in a class, being 
at the same time very steady on the table. It can only be used in a 


Fic. 127. 


engi 
iu 


| 


hi 

horizontal position. The body-tube is focused by the rack and milled 
heads at the top, while the stage and mirror, which slide on the 
horizontal bar, are raised or lowered by the milled heads at the side of 
the standard. The shifting of the object from right to left is effected 
by the hands. 

Nachet’s Microscope with Large Field.,—A. Gravis describes a 
new Microscope by M. A. Nachet, of which the speciality appears to 
be that it affords a larger field of view than usual in Continental 


* See this Journal, iii. (1883) p. 113. 
+ Bull. Soc. Belg. Micr., x. (1884) pp. 194-7, 


798 SUMMARY OF CURRENT RESEARCHES RELATING TO 


Microscopes, and is thus specially adapted for dissecting, examining 
large sections, &c. The tube has an interior diameter of 29 mm., 
and the apparent diameter of the field measured at a distance of 
250 mm. by means of the camera lucida is 200 mm. With the 
ordinary Nachet No. 1 eye-piece this diameter is only 185 mm., and 
with No. 1 Prazmowski 110 mm. There is a variable objective, which 
when shortened gives a magnifying power of 15 with a working distance 
of 28 mm. and real diameter of 13 mm. When extended these figures 
are 23, 7 mm. and 8°5 mm. respectively. 


Stephenson’s Aquarium Microscope.—This Microscope (fig. 128) 
was designed by Mr. J. W. Stephenson for the examination of living 
objects in an aquarium. 


Fia. 128. 


JTAVTAUTEALEUAEAAACCE LECTUS CET 


TTA 
we 


A brass bar is laid across the aquarium, as shown in the woodcut. 
To adjust it to aquaria of different widths the support on the left is 
made to slide along the bar, and it can be clamped at any given point 
by the upper milled head. The milled head at the side, by pressing 
on a loose plate, fastens the bar securely to the aquarium. 

Between the ends of the bar slides an arm carrying a sprung 
socket, and the arm can be clamped at any given point of the bar. 
Through the socket is passed a glass cylinder, cemented to a brass 
collar at the upper end and closed at the lower by a piece of cover- 


ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 799 


glass. Into this cylinder is screwed the body-tube of the Microscope 
with eye-piece and objective, which are thus pr otected from the water 
of the aquarium. The Microscope is focused by rack and pinion 
(milled head just below the eye- -piece), and in addition the objective 
is screwed to a draw tube so that its position in the cylinder may be 
approximately regulated. 

The arm of the socket is hinged to allow of the Microscope being 
inclined in a plane parallel to the sides of the aquarium. ‘The lower 
milled head clamps the hinge at any desired inclination. The socket 
also rotates on the arm so that the Microscope can be inclined in a 
plane parallel to the front of the aquarium. Thus any point of the 
aquarium can be reached. 

Swift and Son’s Oxyhydrogen Microscope. — This (fig. 129) 
is suitable for use with ordinary objectives from 4 in. to 1/4 in. 
The gas jet can be regulated for either parallel or convergent light 
without the necessity of opening the lantern, it being mounted on 


Fie. 129.